Mutational Analysis Reinforces the Diagnosis of Nodal Marginal Zone Lymphoma With Robust PD1-positive T-Cell Hyperplasia
No abstract available (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Letter to the Editor Source Type: research

Multifocal Renal Cell Carcinomas With Somatic IDH2 Mutation: Report of a Previously Undescribed Neoplasm
This study associates the discovery of a new histologic presentation of RCC with the first report of an IDH2 gain-of-function mutation in RCC. (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Case Report Source Type: research

Hepatoid Teratoma, Hepatoid Yolk Sac Tumor, and Hepatocellular Carcinoma: A Morphologic and Immunohistochemical Study of 30 Cases
Rare hepatoid teratomas (HTs) in testicular germ cell tumor patients mimic hepatoid yolk sac tumor (HYST) and hepatocellular carcinoma (HCC). We compared the features of 2 metastatic HTs, 12 HYSTs, and 16 HCCs. The mean ages were 36, 40, and 62.5 years, respectively. The HTs formed sheets of hepatocyte-like cells with macrovesicular fat arranged in vague lobules with intervening fibrous bands containing biliary ductule–like structures and abortive portal triads. HTs lacked basement membrane deposits, with hepatoid cells staining for glypican-3, arginase, and HepPar-1 (2/2), whereas stains for CK19 (2/2) and CK7 (1/2)...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Original Articles Source Type: research

AKT1 Mutations in Peripheral Bronchiolar Papilloma: Glandular Papilloma and Mixed Squamous Cell and Glandular Papilloma Is Distinct From Bronchiolar Adenoma
Glandular papilloma (GP) and mixed squamous cell and glandular papilloma (MP) are rare benign pulmonary tumors occurring in the bronchi. Bronchiolar adenoma (BA) was recently characterized as a pulmonary tumor exhibiting alveolar spread. Both GP/MP and BA are composed of a mixture of glandular, ciliated, squamous, and basal cells. We aimed to clarify whether GP/MP and BA represent the same tumor. We evaluated the detailed histologic characteristics of 11 cases involving pulmonary peripheral tumors that exhibited histologic features of GP/MP or BA, and performed genetic analyses using targeted panel sequencing, allele-speci...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Original Articles Source Type: research

Clinicopathologic Significance of EGFR Mutation and HPV Infection in Sinonasal Squamous Cell Carcinoma
Sinonasal squamous cell carcinoma (SNSCC) is sometimes associated with high-risk human papillomavirus (HR-HPV) infection and inverted sinonasal papilloma or oncocytic sinonasal papilloma. Frequent mutations of EGFR and KRAS are reported in inverted sinonasal papilloma–related sinonasal squamous cell carcinoma (ISP-SCC) and oncocytic sinonasal papilloma–related SNSCC, respectively. Here, we attempted to determine the prevalence and the prognostic significances of these alterations in SNSCC. We retrospectively collected 146 SNSCCs, including 14 ISP-SCCs, and comprehensively analyzed the HR-HPV infection by human ...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Original Articles Source Type: research

A Proposed Staging System for Improved Prognostication of MDM2-amplified Liposarcoma
Despite the release of anatomic site-specific staging systems for soft tissue sarcomas in the eighth edition of the American Joint Committee on Cancer (AJCC) Cancer Staging Manual, the algorithms for sarcomas arising in the extremities/trunk and retroperitoneum differ only in the staging of lymph node metastasis. The retroperitoneum not only provides a larger potential space for tumor growth before the clinical presentation, but its anatomic complexities complicate surgical resection and adversely affect disease-free survival. Here, we propose a new staging system for MDM2-amplified liposarcomas (well-differentiated and de...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Original Articles Source Type: research

Immunohistochemical Characterization of Giant Cell Tumor of Bone Treated With Denosumab: Support for Osteoblastic Differentiation
Giant cell tumor of bone is a locally aggressive, rarely metastasizing neoplasm. Evidence suggests that the neoplastic cells may be osteoblastic in differentiation. Standard treatment is surgical removal, but medical therapy with denosumab, an inhibitor of receptor activator of nuclear factor-κβ ligand, has become a component of patient management in select cases. Denosumab-treated giant cell tumor of bone (DT-GCTB) shows drastic morphologic changes including the presence of abundant bone. To further determine the relationship of the neoplastic cells to osteoblast phenotype, we performed a morphologic and immuno...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Original Articles Source Type: research

Genomic Profiling Aids Classification of Diagnostically Challenging Uterine Mesenchymal Tumors With Myomelanocytic Differentiation
Although diagnosis of high-grade uterine mesenchymal tumors (UMTs) exhibiting classic morphologic features is straightforward, diagnosis is more challenging in tumors in which prototypical features are poorly developed, focal, and/or coexist with features seen in other neoplasms. Here, we sought to define the repertoire of somatic genetic alterations in diagnostically challenging UMTs with myomelanocytic differentiation, including some reported as perivascular epithelioid cell tumors (PEComas). In 17 samples from 15 women, the tumors were histologically heterogenous. Immunohistochemical expression of at least 1 melanocytic...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Original Articles Source Type: research

CTNNB1 Mutations and Aberrant β-Catenin Expression in Ovarian Endometrioid Carcinoma: Correlation With Patient Outcome
CTNNB1 mutations and aberrant β-catenin expression have adverse prognosis in endometrial endometrioid carcinoma, and recent evidence suggests a prognostic role of β-catenin in ovarian endometrioid carcinoma. Thus, we aimed to determine the prognostic value of the CTNNB1 mutational status, and its correlation with β-catenin expression, in a well-annotated cohort of 51 ovarian endometrioid carcinomas. We performed immunohistochemistry for β-catenin and developed an 11-gene next-generation sequencing panel that included whole exome sequencing of CTNNB1 and TP53. Results were correlated with clinicopatholog...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Original Articles Source Type: research

Sertoli-Leydig Cell Tumors of the Ovary With Follicular Differentiation Often Resembling Juvenile Granulosa Cell Tumor: A Report of 38 Cases Including Comments on Sex Cord-Stromal Tumors of Mixed Forms (So-called Gynandroblastoma)
Thirty-eight ovarian Sertoli-Leydig cell tumors that contained follicles are described; in 33 of them follicles imparted a microscopic appearance resembling that of the juvenile granulosa cell tumor. The average age of the patients (28 y), frequency of androgenic manifestations (40%), and dominant histopathologic features were all typical of Sertoli-Leydig cell tumor, mostly (80%) of intermediate differentiation. The remaining tumors were poorly differentiated; none were well differentiated. The follicles that mimicked juvenile granulosa cell tumor accounted for ∼5% to 40% of the tumor volume. They typically aro...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Original Articles Source Type: research

Malignant Mesothelioma of the Peritoneum in Women: A Clinicopathologic Study of 164 Cases
In this study, we present the clinicopathologic features of 164 such cases seen in our institution over a period of 42 years (1974-2016). Clinical information, pathologic findings, immunohistochemical results, and follow-up were recorded. Hematoxylin and eosin–stained slides were reviewed in all cases. Patients ranged in age from 3 to 85 years, median: 49 years. Most patients presented with abdominal/pelvic pain, although some were asymptomatic, presented with paraneoplastic syndromes or cervical lymphadenopathy. Overall, 9% of patients had a history of direct or indirect exposure to asbestos. In total, 31% and 69% o...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Original Articles Source Type: research

Rosai-Dorfman Disease Displays a Unique Monocyte-Macrophage Phenotype Characterized by Expression of OCT2
In this study, we characterized the histologic and phenotypic features in 33 RDD patients to better define the pathologic diagnosis. Cases included 24 patients with extracutaneous disease (“R” group), and 9 patients with lesions limited to the skin or subcutaneous tissue (“C” group). We identified OCT2 as a novel marker for the monocyte-macrophage phenotype of RDD, expressed in 97% of RDD cases. In contrast, OCT2 expression was seen in 0% of Erdheim-Chester disease cases and 6.7% of Langerhans cell histiocytosis cases. Other markers useful in the diagnosis of RDD included S100 (100%), CD163 (88%), a...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Original Articles Source Type: research

Alterations in Ki67 Labeling Following Treatment of Poorly Differentiated Neuroendocrine Carcinomas: A Potential Diagnostic Pitfall
Assessment of the Ki67 index is critical for grading well-differentiated neuroendocrine tumors (WD-NETs), which can show a broad range of labeling that defines the WHO grade (G1-G3). Poorly differentiated neuroendocrine carcinomas (PD-NECs) have a relatively high Ki67 index,>20% in all cases and commonly exceeding 50%. After anecdotally observing PD-NECs with an unexpectedly low and heterogeneous Ki67 index following chemotherapy in 5 cases, we identified 15 additional cases of treated high-grade neuroendocrine neoplasms (HG-NENs). The study cohort comprised 20 cases; 11 PD-NECs, 8 mixed adenoneuroendocrine carcinomas, ...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Original Articles Source Type: research

Comparison of RNA In Situ Hybridization and Immunohistochemistry Techniques for the Detection and Localization of SARS-CoV-2 in Human Tissues
Coronavirus disease-19 (COVID-19) is caused by a newly discovered coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although SARS-CoV-2 is visualized on electron microscopy, there is an increasing demand for widely applicable techniques to visualize viral components within tissue specimens. Viral protein and RNA can be detected on formalin-fixed paraffin-embedded (FFPE) tissue using immunohistochemistry (IHC) and in situ hybridization (ISH), respectively. Herein, we evaluate the staining performance of ISH for SARS-CoV-2 and an IHC directed at the SARS-CoV nucleocapsid protein and compare these res...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Original Articles Source Type: research

Molecular Profiling of Clear Cell Myoepithelial Carcinoma of Salivary Glands With EWSR1 Rearrangement Identifies Frequent PLAG1 Gene Fusions But No EWSR1 Fusion Transcripts
Myoepithelial carcinoma of salivary glands is an underrecognized and challenging entity with a broad morphologic spectrum, including an EWSR1-rearranged clear cell variant. Myoepithelial carcinoma is generally aggressive with largely unknown genetic features. A retrospective review of Salivary Gland Tumor Registry in Pilsen searching for the key words “clear cell myoepithelial carcinoma,” “hyalinizing clear cell,” and “clear cell malignant myoepithelioma” yielded 94 clear cell myoepithelial carcinomas (CCMCs) for molecular analysis of EWSR1 rearrangement using fluorescence in situ hybrid...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Original Articles Source Type: research

The 2020 WHO Classification: What’s New in Soft Tissue Tumor Pathology?
The fifth edition of the World Health Organization Classification of Tumors of Soft Tissue and Bone was published in early 2020. The revisions reflect a consensus among an international expert editorial board composed of soft tissue and bone pathologists, geneticists, a medical oncologist, surgeon, and radiologist. The changes in the soft tissue tumor chapter notably include diverse, recently described tumor types (eg, atypical spindle cell/pleomorphic lipomatous tumor, angiofibroma of soft tissue, and CIC-rearranged sarcoma), new clinically significant prognostic information for a variety of existing entities (eg, dediffe...
Source: The American Journal of Surgical Pathology - December 16, 2020 Category: Pathology Tags: Special Article Source Type: research

Endometrial Gastric-type Carcinoma: An Aggressive and Morphologically Heterogenous New Histotype Arising From Gastric Metaplasia of the Endometrium
No abstract available (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Letter to the Editor Source Type: research

SRF Fusions Other Than With RELA Expand the Molecular Definition of SRF-fused Perivascular Tumors
Pericytic tumors encompass several entities sharing morphologic and immunohistochemical features. A subset of perivascular myoid tumors associated with the SRF-RELA fusion gene was previously described. Herein, we report a series of 13 tumors belonging to this group, in which we have identified new fusion genes by RNA-sequencing, thus expanding the molecular spectrum of this entity. All patients except 1 were children and infants. The tumors, frequently located in the head (n=8), had a mean size of 38 mm (range 10 to 150 mm) and were mostly (n=9) well-circumscribed. Exploration of the follow-up data (ranging ...
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

BRG1, INI1, and ARID1B Deficiency in Endometrial Carcinoma: A Clinicopathologic and Immunohistochemical Analysis of a Large Series From a Single Institution
This study immunohistochemically examined the expression status of BRG1, INI1, and ARID1B using 570 archived cases of endometrial carcinoma and carcinosarcoma resected at a single institution. We identified 1 BRG1-deficient undifferentiated carcinoma, 8 BRG1/INI1/ARID1B–deficient DC, and 3 BRG1-deficient clear-cell carcinomas. None of the cases of endometrioid and serous carcinomas or carcinosarcoma showed deficiencies of these subunits. We then compared 8 BRG1/INI1/ARID1B–deficient DC with 6 BRG1/INI1/ARID1B–intact DC and 28 carcinosarcomas, the latter of which was often confused with DC. Histologically,...
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

Secondary Involvement of the Uterine Cervix by Nongynecologic Neoplasms: A Detailed Clinicopathologic Analysis
Secondary involvement of the uterine cervix by nongynecologic neoplasms is rare accounting for 50.5) (P=0.01). Mean time to identification of cervical metastases was (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

Optimal Criteria for G3 (Poorly Differentiated) Stage II Colon Cancer: Prospective Validation in a Randomized Controlled Study (SACURA Trial)
Grade 3 (G3, poorly differentiated) is an important treatment-decision factor in stage II colon cancer, but no unified diagnostic criteria are established. According to previous studies, an intratumoural poorly differentiated area with no glandular formation (POR) that fills the microscopic field of a ×40 objective lens was an essential factor that defined G3. We aimed to prospectively validate this in a randomized controlled study of adjuvant chemotherapy (SACURA trial). We enrolled 991 patients with stage II colon cancer. POR was graded according to the ×40 objective lens rule and the intensity of poorly diff...
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

Recurrent YAP1 and MAML2 Gene Rearrangements in Retiform and Composite Hemangioendothelioma
Retiform and composite hemangioendotheliomas (CHEs) are both locally aggressive, rarely metastasizing vascular neoplasms characterized by arborizing vascular channels lined by endothelial cells with a hobnail morphology. CHE displays additional cytologic and architectural components, including often vacuolated epithelioid cells, solid areas, or features reminiscent of well-differentiated angiosarcoma. Triggered by an index case of a soft tissue retiform hemangioendothelioma (RHE) which revealed a YAP1-MAML2 gene fusion by targeted RNA sequencing, we sought to investigate additional cases in this morphologic spectrum for th...
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

Histopathologic Characterization of Mogamulizumab-associated Rash
Rash is one of the most common adverse events observed with mogamulizumab, an anti-C-C chemokine receptor 4 monoclonal antibody approved for previously treated mycosis fungoides (MF) and Sezary syndrome (SS). Given the nonspecific clinical presentations of this rash, histopathologic distinction from MF/SS is critical for informing clinical management. We performed a comprehensive characterization of the histopathologic findings in mogamulizumab-associated rash (MAR) with the integration of high-throughput sequencing of T-cell receptor (TCR) genes. Fifty-two biopsy specimens from 19 patients were evaluated retrospectively. ...
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

Langerhans Cell Histiocytosis Associated With Renal Cell Carcinoma Is a Neoplastic Process: Clinicopathologic and Molecular Study of 7 Cases
We describe 7 patients who presented with LCH occurring within (6 cases) or after (1 case) a resected clear cell (n=6) or clear cell papillary (n=1) renal cell carcinoma (RCC), identified prospectively in our routine and consultation files (2012 to 2019). The patients included 5 women and 2 men, with a median age of 54 years (range, 39 to 73 y), none with a history of LCH or LCH manifestations before the time of RCC diagnosis. The median size of the RCC was 3.5 cm (range, 1.8 to 8.3 cm). Treatment included partial (5 cases), or radical (2 cases) nephrectomy. All RCCs on gross examination showed at leas...
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

Mural Intracholecystic Neoplasms Arising in Adenomyomatous Nodules of the Gallbladder: An Analysis of 19 Examples of a Clinicopathologically Distinct Entity
In conclusion, these cases highlight a distinct clinicopathologic entity, that is, mural ICNs arising in adenomyomatous nodules, which, by essentially sparing the “main” mucosa, not displaying “field-effect/defect” phenomenon, and only rarely (16%) showing carcinomatous transformation, are analogous to pancreatic branch duct intraductal papillary mucinous neoplasms. (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

Claudin-18 as a Marker for Identifying the Stomach and Pancreatobiliary Tract as the Primary Sites of Metastatic Adenocarcinoma
In conclusion, claudin-18 represents a sensitive and specific marker for stomach and pancreatobiliary adenocarcinoma that may be a useful diagnostic tool in routine surgical pathology. (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

Clinicopathologic Study of Gleason Pattern 5 Prostatic Adenocarcinoma With “Single-cell” Growth Reveals 2 Distinct Types, One With “Plasmacytoid” Features
Each Gleason score category of prostatic adenocarcinoma (or Grade Group) may encompass a diverse group of architectural patterns such as well-formed glands, poorly formed glands, cribriform structures, single cells, and/or solid sheets. We have noted heterogeneity within the single-cell subtype of Gleason pattern 5 prostatic adenocarcinoma that has not been fully addressed. Therefore, we retrospectively reviewed a series of radical prostatectomies with high-grade prostatic adenocarcinoma (Grade Group 4 or 5), identifying tumors with a component of single-cell infiltration. Additional cases identified prospectively were als...
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

FUS-NFATC2 or EWSR1-NFATC2 Fusions Are Present in a Large Proportion of Simple Bone Cysts
A simple bone cyst (SBC) is a benign bone lesion of unknown etiology. It can be differentiated from an aneurysmal bone cyst (ABC) by radiologic and histopathologic features, as well as by the absence of fusions of the USP6 gene characteristic of an ABC. In an attempt to differentiate between ABC and SBC in a recurrent bone cyst, we performed targeted RNA sequencing and found an EWSR1-NFATC2 fusion and no fusion of the USP6 gene. We subsequently analyzed additional 10 cysts, consistent with SBCs after radiologic-pathologic correlation, for the presence of an NFATC2 gene fusion, by targeted RNA sequencing, reverse-transcript...
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

Molecular Profiling of Salivary Oncocytic Mucoepidermoid Carcinomas Helps to Resolve Differential Diagnostic Dilemma With Low-grade Oncocytic Lesions
Oncocytic mucoepidermoid carcinoma (OMEC) is a rare but diagnostically challenging variant of mucoepidermoid carcinoma (MEC). OMEC is notable for differential diagnostic considerations that are raised as a result of overlap with other benign and low-grade oncocytic salivary gland tumors. Diffuse and strong immunoreactivity of p63 protein may be useful in distinguishing OMEC from its mimics. However, focal p63 staining can be present in benign oncytomas. Presence of mucin-containing cells, mucinous cystic formation, and foci of extravasated mucin are considered a hallmark of MEC. True mucocytes may be, however, very few and...
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

High-grade B-Cell Lymphoma With MYC, BCL2, and/or BCL6 Translocations/Rearrangements: Clinicopathologic Features of 51 Cases in a Single Institution of South China
Double-hit/triple-hit lymphomas (DH/THLs) are high-grade B-cell lymphomas with MYC and BCL2 rearrangements and/or BCL6 rearrangements, which have poor outcomes after standard chemoimmunotherapy. This retrospective study analyzed 51 patients (range, 19 to 82 y) diagnosed from 2016 to 2019 and treated for DH/THL (n=34 MYC/BCL6 DHL, n=14 MYC/BCL2 DHL, n=3 THL) at one institution in South China. Extranodal lesions occurred in 32 patients (62.7%), more frequently in MYC/BCL6 DHL (22/34, 64.7%) than in MYC/BCL2 DHL (7/14, 50%). The most common extranodal sites were the stomach (8/32, 25.0%) and intestine (5/32, 15.6%). Mo...
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

Primary Female Urethral Carcinoma: Proposed Staging Modifications Based on Assessment of Female Urethral Histology and Analysis of a Large Series of Female Urethral Carcinomas
This study of one of the largest cohort of primary female urethral carcinomas provides a modified histology-based staging system specific to female urethral anatomy that provides outcomes-related information, which may be further validated by larger multi-institutional studies. (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

Chondroblastoma Expresses RANKL by RNA In Situ Hybridization and May Respond to Denosumab Therapy
Lesions of bone featuring osteoclast-like giant cells comprise a diverse group of entities, including giant cell tumor (GCT) of bone, chondroblastoma, and aneurysmal bone cyst, among others. The receptor activator of nuclear factor-κB ligand (RANKL) has been implicated in the pathogenesis of GCT of bone and may play a role in the pathogenesis of other giant cell–rich lesions as well. In addition, RANKL inhibitors (denosumab) have also been shown to have some efficacy in treating some giant cell–rich lesions. Herein, we examine RANKL expression by RNA in situ hybridization in a total of 84 osseous lesions ...
Source: The American Journal of Surgical Pathology - November 18, 2020 Category: Pathology Tags: Original Articles Source Type: research

DNA Mismatch Repair–deficient Endometrial Carcinosarcomas Portend Distinct Clinical, Morphologic, and Molecular Features Compared With Traditional Carcinosarcomas
Uterine carcinosarcomas (UCSs) are aggressive neoplasms composed of high-grade malignant epithelial and mesenchymal elements with most (∼90%) showing TP53 abnormalities. A subset, however, shows mismatch repair deficiency (MMR-D). We sought to describe their clinical, morphologic, and molecular features. Clinicopathologic data of MMR-D UCSs were recorded including age, stage, follow-up, mismatch repair and p53 immunohistochemistry (IHC), MLH1 promoter methylation status, and germline alterations, TP53 mutation status, microsatellite instability and mutational burden by massively parallel sequencing. Seventeen (6.2%) MM...
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

Uterine Tumor Resembling Ovarian Sex Cord Stromal Tumor (UTROSCT): A Series of 3 Cases With Extensive Rhabdoid Differentiation, Malignant Behavior, and: ESR1-NCOA2: Fusions
This study is the first to highlight an association between UTROSCTs with extensive rhabdoid differentiation, ESR1-NCOA2 fusions, and aggressive behavior. UTROSCTs are considered neoplasms of uncertain malignant potential, but have a benign course in most cases. Thus, it is important to be aware of these specific features and recommend long-term follow-up due to their propensity for late recurrences. (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

A Molecular Reappraisal of Glomus Tumors and Related Pericytic Neoplasms With Emphasis on NOTCH-gene Fusions
This study aimed to investigate the prevalence and specificity of NOTCH-gene fusions in a large group of GT and correlate with clinical features. BRAF-VE1 and PDGFRB immunoexpression was also investigated in this cohort. A total of 93 GT and 43 other pericytic lesions (11 MP, 13 MF, and 19 AL) were selected. All cases were tested by fluorescence in situ hybridization for NOTCH1-4 and MIR143 gene abnormalities and 6 cases were investigated by targeted RNA-sequencing. Fluorescence in situ hybridization revealed NOTCH-gene rearrangements in 50 (54%) GT, 2 MP (18%), and 2 AL (11%). NOTCH-rearrangements were present in 34 (68%)...
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

Clinicopathologic Features of Low-grade Appendiceal Mucinous Neoplasm: A Single-institution Experience of 117 Cases
Low-grade appendiceal mucinous neoplasm (LAMN) is an enigmatic tumor that lacks the capacity for classic invasion but can dissect through the appendiceal wall, causing pseudomyxoma peritonei (PMP). Most large studies of the histologic spectrum of LAMN and its rate of associated PMP include cases submitted from outside institutions, potentially skewing their findings. We identified 117 cases of LAMN at our institution. Hematoxylin and eosin-stained slides from each were reviewed, and clinical and pathologic parameters were noted. The patients were 76 females and 41 males, with a mean age of 60 years. Presenting symptoms wer...
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

Molecular Characterization of Neuroendocrine Carcinomas of the Endometrium: Representation in All 4 TCGA Groups
High-grade neuroendocrine carcinomas (NEC) of the endometrium are rare and account for (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

Primary Pulmonary Myxoid Sarcoma and Myxoid Angiomatoid Fibrous Histiocytoma: A Unifying Continuum With Shared and Distinct Features
We report a case of primary pulmonary low-grade myxoid spindle cell tumor with morphologic and immunohistochemical features of PPMS but with an EWSR1-ATF1 fusion gene. In addition, we also encountered a case of endobronchial AFH with EWSR1-CREB1 translocation but also focal morphologic features of PPMS. These findings provide new evidence supporting the concept that PPMS and a myxoid variant of AFH represent a continuum with overlapping histologic, immunohistochemical, and genetic features. (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

Helicobacter pylori Antigen But Not the Organism Is Occasionally Present Within Germinal Centers: Implications for Patient Management and Biology
Helicobacter pylori infection is present in two thirds of the world’s population and induces a myriad of human diseases, ranging from gastritis to gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma. Detection is critical for treatment and may require immunohistochemical (IHC) staining when organisms are not visible on hematoxylin and eosin. We have encountered cases in which IHC for Helicobacter pylori failed to demonstrate curvilinear or coccoid organisms, but did show a reticular pattern of immunoreactivity involving the underlying germinal centers. We performed a systematic retrospective evaluat...
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

The Width of Invasion in Malignant Melanoma Is a Novel Prognostic Feature That Accounts for Outcome Better Than Breslow Thickness
Breslow thickness (BT) is the cornerstone of malignant melanoma staging. However, to our knowledge no-one has ever assessed the horizontal width of invasion, measured microscopically, as a prognostic feature. This was investigated as a prognostic feature in this study. A retrospective cohort of 1329 melanoma cases was collected from patients presenting to a UK teaching hospital from January 1, 2004, to December 31, 2014. The main outcome was overall survival (OS). We found that width was associated with OS in multivariable analysis (hazard ratio=1.05, 95% confidence interval: 1.03-1.07, P (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

Intravascular Lobular Capillary Hemangioma (Intravascular Pyogenic Granuloma): A Clinicopathologic Study of 40 Cases
Intravascular lobular capillary hemangioma (ILCH), or intravascular pyogenic granuloma, is relatively rare and likely underrecognized. We reviewed all ILCH cases from our institution confirmed pathologically from 2006 to 2019. Immunostains for smooth muscle actin and Wilms tumor 1 were performed on all cases and prior immunohistochemical stains were reviewed. Forty cases were identified (22 females; 18 males) with a median age of 53 years (range: 13 to 85 y). Clinically, all were well-circumscribed, stable to slow-growing raised/cystic skin lesions ranging from 1 to 40 mm. Most were located on the upper extre...
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

HPV-independent Precursors Mimicking High-grade Squamous Intraepithelial Lesions (HSIL) of the Vulva
In conclusion, about one fifth of the HPV-independent precursors mimic HSIL, showing either basaloid or warty features. Older age and the presence of areas of typical HPV-independent intraepithelial lesions, together with p16 negativity, should raise suspicion of an HPV-independent etiology. (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

Chromogranin A Expression in Rectal Neuroendocrine Tumors Is Associated With More Aggressive Clinical Behavior and a Poorer Prognosis
Although rectal neuroendocrine tumors (NETs) with an L-cell phenotype and small size are generally less clinically serious, the new 2019 World Health Organization (WHO) classification system has categorized all of these lesions as malignant. Identifying biomarkers of rectal NETs is thus important for stratifying their clinical behavior. Chromogranin A protein expression was assessed in 538 endoscopically or surgically resected rectal NETs and compared with clinicopathologic factors to identify its clinical and prognostic significance. All of the rectal NETs analyzed (100%) were synaptophysin positive, but chromogranin A la...
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

Synovial Sarcoma of the Female Genital Tract: A Protean Mimic of Müllerian Neoplasia
Synovial sarcoma most commonly occurs in the extremities but has rarely been described in the female genital tract. In this series, we describe the clinical, morphologic, immunohistochemical, and molecular features of 7 cases of vulvovaginal synovial sarcoma (vulva, n=6; vagina, n=1). We emphasize their wide morphologic spectrum, which can overlap significantly with other more common tumors at these sites, as highlighted by 2 cases initially diagnosed as other entities (endometrioid carcinoma and malignant peripheral nerve sheath tumor). The average patient age was 41 (range: 23 to 62) years and tumor size ranged from 0.8 ...
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

Acquired Cystic Kidney Disease–associated Renal Cell Carcinoma (ACKD-RCC) Harbor Recurrent Mutations in KMT2C and TSC2 Genes
Individuals with acquired cystic kidney disease (ACKD) in the setting of end-stage renal disease (ESRD) have a high risk of developing renal cell carcinoma (RCC). ACKD-RCC is considered a distinct renal neoplasm in the International Society of Urologic Pathologists (ISUP)-World Health Organization (WHO) classification of kidney tumors which may behave aggressively. Since its original description, there have been multiple case reports and series published; however, the pathogenesis of this neoplasm is uncertain and there is limited data on the genetic aberrations of this tumor. Herein, we present our experience with ESRD ki...
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

Plexiform Myofibroblastoma: Clinicopathologic Analysis of 36 Cases of a Distinctive Benign Tumor of Soft Tissue Affecting Mainly Children and Young Adults
The spectrum of benign superficial fibroblastic/myofibroblastic tumors continues to expand and includes entities such as plexiform fibrohistiocytic tumor, dermatomyofibroma and fibroblastic connective tissue nevus. Here, we describe a seemingly distinctive group of lesions which we have labeled “plexiform myofibroblastoma” (PM). PM is a rare superficial mesenchymal tumor of fibroblastic/myofibroblastic lineage that predominantly occurs in children and young adults. Thirty-six cases from the consultation archives of one of the authors have been studied to characterize the clinicopathologic characteristics of PM....
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

CNS Low-grade Diffusely Infiltrative Tumors With INI1 Deficiency, Possessing a High Propensity to Progress to Secondary INI1-deficient Rhabdoid Tumors
In conclusion, CNS LGDIT-INI1 may represent a rare group of tumors that are clinically indolent but have a high propensity to progress to RT. (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

Morphologic and Immunohistochemical Characteristics of Fluorescent In Situ Hybridization Confirmed TFE3-Gene Fusion Associated Renal Cell Carcinoma: A Single Institutional Cohort
TFE3-fusion associated renal cell carcinoma (TFE3-RCC) accounts for up to 5% adults and 40% of childhood RCC. Their comprehensive immunohistochemical (IHC) profile in correlation to fluorescence in situ hybridization (FISH) testing and their role in the diagnostic approach are not well documented because of lacking published data. FISH confirmed TFE3-RCC between years 2010 and 2020 were identified from institutional electronic database and retrospectively reviewed. Eighty-five TFE3-RCC were identified. Seventy-six of 85 (89.4%) TFE3-RCC cases had positive TFE3 expression, with diffuse and strong/moderate TFE3 expression in...
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

Inflammatory Myofibroblastic Tumor of the Uterus: An Immunohistochemical Study of 23 Cases
Inflammatory myofibroblastic tumors (IMT) of the uterus may be underrecognized as their morphology and immunophenotype may overlap with myxoid variants of uterine smooth muscle tumors and endometrial stromal tumors. Although ALK is a helpful biomarker, not all uterine IMTs are ALK-rearranged, and a small subset of myxoid leiomyosarcomas is ALK-positive. Herein, we evaluated a series of 23 IMTs for the novel endometrial stromal markers interferon-inducible transmembrane protein-1 (IFITM1) and BCOR, the novel myoid marker transgelin, and possible predictive markers p16 and p53 by immunohistochemistry to determine their expre...
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Original Articles Source Type: research

The Separation of Benign and Malignant Mesothelial Proliferations: New Markers and How to Use Them
The separation of benign from malignant mesothelial proliferations is an important clinical but often a difficult morphologic problem. Over the last roughly 10 years a variety of new markers that aid in this separation have been published and some older recommended markers reconsidered. Unlike previous, and largely unusable, empiric immunohistochemical (IHC) stains, these new markers, some using IHC and some using fluourescent in situ hybridization (FISH), are largely based on documented genomic abnormalities in malignant mesotheliomas. However, no marker works in all situations; rather, markers need to be chosen by the mo...
Source: The American Journal of Surgical Pathology - October 14, 2020 Category: Pathology Tags: Special Article Source Type: research