Reply to: Expanding the Spectrum of Primary Cutaneous Carcinoma With BRD3-NUTM1 Fusion
No abstract available (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Letters to the Editor Source Type: research

Cutaneous Primary NUT Carcinoma With BRD3-NUTM1 Fusion
No abstract available (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Letters to the Editor Source Type: research

OGT-rearranged Acral Mesenchymal Neoplasms: An Emerging Entity With an Expanding Pathologic and Molecular Spectrum
No abstract available (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Letters to the Editor Source Type: research

p16 Immunoreactivity Correlates With Morphologic Diagnosis of HPV-associated Anal Intraepithelial Neoplasia: A Study of 1000 Biopsies
p16 is the most useful diagnostic marker for human papillomavirus (HPV)-associated anogenital lesions. In the cervix, the pattern of p16 immunoreactivity generally correlates with lesion severity. p16 expression in anal intraepithelial neoplasia (AIN) is far less studied. Whether such correlation holds true has to be determined. We correlated the degree and pattern of p16 immunohistochemistry (IHC) results with morphologic diagnoses of 1000 anal squamous and transitional zone biopsy specimens. Using the Lower Anogenital Squamous Terminology criteria, p16 IHC results were classified as block staining, partial staining, or n...
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

Morphologic Spectrum of Lymphadenopathy in Adult-onset Immunodeficiency (Anti-interferon-γ Autoantibodies)
We describe the morphologic features and the results of ancillary studies, including special stains, immunohistochemistry, and molecular testing. The overall median age of these patients was 60.5 years (range, 41 to 83 y) with a male-to-female ratio of 20:16. All biopsy specimens showed nontuberculous mycobacterial infection, and most cases showed the following histologic features: capsular thickening with intranodal sclerosing fibrosis, irregularly distributed ill-formed granulomas or histiocytic aggregates with neutrophilic infiltration, interfollicular expansion by a polymorphic infiltrate with some Hodgkin-like ...
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

A Novel NIPBL-NACC1 Gene Fusion Is Characteristic of the Cholangioblastic Variant of Intrahepatic Cholangiocarcinoma
We report a novel NIPBL-NACC1 gene fusion in a rare primary hepatic neoplasm previously described as the “cholangioblastic variant of intrahepatic cholangiocarcinoma.” The 2 index cases were identified within our consultation files as morphologically distinctive primary hepatic neoplasms in a 24-year-old female and a 54-year-old male. The neoplasms each demonstrated varied architecture, including trabecular, organoid, microcystic/follicular, and infiltrative glandular patterns, and biphasic cytology with large, polygonal eosinophilic cells and smaller basophilic cells. The neoplasms had a distinctive immunoprof...
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

Recurrent YAP1-TFE3 Gene Fusions in Clear Cell Stromal Tumor of the Lung
Clear cell (hemangioblastoma-like) stromal tumor of the lung (CCST-L) is a recently described distinctive rare pulmonary neoplasm of unknown histogenesis and molecular pathogenesis. Only 7 cases have been reported in 2 recent studies, although additional cases might have been reported under the heading of extraneural pulmonary hemangioblastoma. We herein describe 4 CCST-L cases, 3 of them harboring a YAP1-TFE3 fusion. The fusion-positive tumors occurred in 3 women, aged 29, 56, and 69 years. All presented with solitary lung nodules measuring 2.3 to 9.5 cm. Histologically, all tumors showed similar features being com...
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

Genetic and Clinical Studies of Patients With Increased Multinucleated Megakaryocytes in Bone Marrow as an Isolated Finding: A Diagnostic Pitfall for Myelodysplastic Syndrome
The presence of increased multinucleated megakaryocytes (aka osteoclast-like) is considered a dysplastic feature in myelodysplastic syndrome; however, its clinical significance in isolation is uncertain. Herein, we report the clinicopathologic and genetic features of 18 such cases of 40,539 bone marrow biopsies spanning 10 years. All 18 patients had ≥25% multinucleated megakaryocytes in otherwise normal bone marrow biopsies, which were evaluated for plasma cell neoplasms (n=9), lymphoma (n=4), or anemia/neutropenia (n=5). None of the 17 patients tested showed acquired cytogenetic abnormalities. Sixteen patients underwen...
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

Intraductal Carcinoma of the Prostate: Extreme Nuclear Size Is Not a Diagnostic Parameter
High-grade prostatic adenocarcinoma involving duct/acinar structures is labeled intraductal carcinoma of the prostate (IDCP). As numerous studies have shown that IDCP is associated with high stage disease with a significant negative impact on cancer-specific survival, accurate diagnosis is crucial to ensure appropriate patient management. The definition of IDCP recommended by 2016 World Health Organization (WHO) classification suggests that cases of IDCP with micropapillary or loose cribriform architecture without comedonecrosis should have cells with ≥6× nuclear enlargement. It is unclear how this size criterion ...
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

TP53 Mutation and Extraneural Metastasis of Glioblastoma: Insights From an Institutional Experience and Comprehensive Literature Review
Extraneural metastases of glioblastoma (GBM), although rare, are becoming an increasingly recognized occurrence. Currently, the biological mechanism underlying this rare occurrence is not understood. To explore the potential genomic drivers of extraneural metastasis in GBM, we present the molecular features of 4 extraneural metastatic GBMs, along with a comprehensive review and analysis of previously reported cases that had available molecular characterization. In addition to our 4 cases, 42 patients from 35 publications are reviewed. To compare the molecular profiles between GBM cases with extraneural metastasis and the g...
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

Spread Through Air Spaces (STAS) in Non−Small Cell Lung Carcinoma: Evidence Supportive of an In Vivo Phenomenon
Tumor spread through air spaces (STAS) is associated with locoregional recurrence in patients undergoing limited resection (LR) for non−small cell lung carcinoma (NSCLC). We hypothesized that the observation of STAS in both the initial LR specimen and the additional resection specimen from the same patient, processed using different knives, would provide evidence that STAS is an in vivo phenomenon contributing to locoregional recurrence. We retrospectively identified patients with NSCLC (9 adenocarcinoma, 1 squamous cell carcinoma) who underwent LR, had STAS in the LR specimen, and underwent additional resection (lob...
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

Hypoplasia of Extrahepatic Biliary Tree and Intrahepatic Cholangiolopathy in Cystic Fibrosis Imperfectly Mimic Biliary Atresia in 4 Infants With Cystic Fibrosis and Kasai Portoenterostomy
Four male infants with cystic fibrosis and prolonged neonatal jaundice underwent Kasai procedure to relieve biliary obstruction due to apparent biliary atresia. The excised remnants had viscid mucus accumulation in hypoplastic gallbladders and distended peribiliary glands. Main hepatic ducts were narrow and/or malformed. Microscopic differences between the gallbladder and extrahepatic bile ducts in cystic fibrosis and sporadic biliary atresia were unequivocal, despite some histologic overlap; no erosive or fibro-obliterative lesions typical of biliary atresia were seen. Common in liver, biopsies were small duct cholangiopa...
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

Pan-TRK Immunohistochemistry Is Highly Correlated With NTRK3 Gene Rearrangements in Salivary Gland Tumors
We examined whole‐tissue sections from 111 SGTs with molecular characterization, including 26 SCs (23 with ETV6-NTRK3 fusion and 3 with ETV6-RET fusion detected by ligation-dependent reverse transcription-polymerase chain reaction, next-generation sequencing and 85 non-SC SGTs (no ETV6-NTRK3 fusion). Immunohistochemistry was performed with a pan‐TRK rabbit monoclonal antibody. When any pan‐TRK staining (nuclear or cytoplasmic with any staining intensity) was considered to indicate positivity, 22 of 23 SCs with ETV6-NTRK3 fusion (95.7%) and 33 of 85 non‐SC (38.8%) salivary neoplasms were positive, mainly basal cell ...
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

Whole-exome Sequencing of Epstein-Barr Virus–associated Pulmonary Carcinoma With Low Lymphocytic Infiltration Shows Molecular Features Similar to Those of Classic Pulmonary Lymphoepithelioma-like Carcinoma: Evidence to Support Grouping Together as One Disease Entity
This study supports the proposal for the usage of the term “EBV-associated pulmonary carcinoma” to encompass the entire morphologic spectrum of this distinct EBV-associated disease entity. (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

Morphologic, Immunohistochemical, and Genetic Differences Between High-grade and Low-grade Fetal Adenocarcinomas of the Lung
In this study, samples of 4 LG-FLAC and 2 HG-FLAC cases were examined, and the clinicopathologic, immunohistochemical (IHC), and mutational differences between the 2 subtypes were analyzed using literature review. Morphologically, LG-FLACs had a pure pattern with complex glandular architecture composed of cells with subnuclear and supranuclear vacuoles, mimicking a developing fetal lung. In contrast, HG-FLACs contained both fetal lung-like (FLL) and CLA components. With regard to IHC markers, β-catenin exhibited a nuclear/cytoplasmic staining pattern in LG-FLACs but a membranous staining pattern in HG-FLACs. Furthermo...
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

Accurate Distinction of Ovarian Clear Cell From Endometrioid Carcinoma Requires Integration of Phenotype, Immunohistochemical Predictions, and Genotype: Implications for Lynch Syndrome Screening
Ovarian clear cell carcinoma (OCCC) and ovarian endometrioid carcinoma (OEC) are both associated with endometriosis but differ in histologic phenotype, biomarker profile, and survival. Our objectives were to refine immunohistochemical (IHC) panels that help distinguish the histotypes and reassess the prevalence of mismatch repair deficiency (MMRd) in immunohistochemically confirmed OCCC. We selected 8 candidate IHC markers to develop first-line and second-line panels in a training set of 344 OCCC/OEC cases. Interobserver reproducibility of histotype diagnosis was assessed in an independent testing cohort of 100 OCC/OEC ini...
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

Cytoplasmic Pattern p53 Immunoexpression in Pelvic and Endometrial Carcinomas With TP53 Mutation Involving Nuclear Localization Domains: An Uncommon But Potential Diagnostic Pitfall With Clinical Implications
This study reports the clinicopathologic features of 31 cases with a TP53 mutation involving nuclear localization, the largest study to date, emphasizing practical strategies for recognizing this uncommon variant and distinguishing it from the p53 wild-type pattern. The study also evaluates the prognostic significance of TP53 mutation involving nuclear localization in the ovarian high-grade serous carcinoma (HGSC) cohort of The Cancer Genome Atlas database. Most of the 31 tumors were advanced stage pelvic or endometrial HGSC. All TP53 mutations were predicted to result in loss of function. The p53 overexpression pattern wa...
Source: The American Journal of Surgical Pathology - October 25, 2021 Category: Pathology Tags: Original Articles Source Type: research

Reply to: Spread Through Air Spaces (STAS): Can an Artifact Really be Excluded?
No abstract available (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Letters to the Editor Source Type: research

Spread Through Air Spaces (STAS): Can an Artifact Really be Excluded?
No abstract available (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Letters to the Editor Source Type: research

E-Cadherin Expression and Blunted Interferon Response in Blastic Plasmacytoid Dendritic Cell Neoplasm
In this study, we investigated by immunohistochemical analysis the expression of E-cadherin (EC) on pDCs in reactive lymph nodes and tonsils, bone marrow, and in BPDCN. We compared the expression of EC in BPDCN to that in leukemia cutis (LC) and cutaneous lupus erythematosus (CLE), the latter typically featuring pDC activation. In BPDCN, we also assessed the immunomodulatory activity of malignant pDCs through the expression of several type I interferon (IFN-I) signaling effectors and downstream targets, PD-L1/CD274, and determined the extent of tumor infiltration by CD8-expressing T cells. In reactive lymph nodes and tonsi...
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

Feasibility and Performance of Elastin Trichrome as a Primary Stain in Colorectal Cancer Resection Specimens: Results of an Interobserver Variability Study
Venous invasion (VI) is a powerful prognostic factor in colorectal cancer (CRC) that is widely underreported. The ability of elastin stains to improve VI detection is now recognized in several international CRC pathology protocols. However, concerns related to the cost and time required to perform and evaluate these stains in addition to routine hematoxylin and eosin (H&E) stains remains a barrier to their wider use. We therefore sought to determine whether an elastin trichrome (ET) stain could be used as a “stand-alone” stain in CRC resections, by comparing the sensitivity, accuracy, and reproducibility of...
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

Lymphoepithelioma-like Intrahepatic Cholangiocarcinoma Is a Distinct Entity With Frequent pTERT/TP53 Mutations and Comprises 2 Subgroups Based on Epstein-Barr Virus Infection
We examined 27 LELCC cases through next-generation sequencing using a panel of genes commonly mutated in primary liver cancers. Alterations in BAP1, ARID1A, ARID2, and PBRM1 were detected through immunohistochemistry. Fluorescence in situ hybridization was performed to analyze FGFR2 fusions and CCND1 amplification. LELCC is histologically classified as predominantly undifferentiated or glandular. Epstein-Barr virus–encoded small RNA (EBER) expression was found in 16 LELCCs. Approximately 50% of LELCCs expressed programmed death-ligand 1 strongly. Notably, recurrent pTERT and TP53 mutations were detected in 9 (38%) an...
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

Urinary Large Cell Neuroendocrine Carcinoma: A Clinicopathologic Analysis of 22 Cases
We present a relatively large retrospective cohort of urinary LCNEC, 20 from the urinary bladder, and 2 from the ureter, from a single institution. The patients included 16 men and 6 women with a median age of 74.5 years. Most LCNEC presented at an advanced stage with tumors invading the muscularis propria and beyond (21/22). Eight cases were pure LCNEC, while 14 cases were mixed with other histologic types, including conventional urothelial carcinoma (n=9), carcinoma in situ (n=7), small cell carcinoma (n=6), and urothelial carcinoma with glandular (n=3) features. Most LCNEC expressed neuroendocrine markers synaptophysin ...
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

IRF8 is a Reliable Monoblast Marker for Acute Monocytic Leukemias
In this study, we tested and validated a monoclonal antibody to IRF8 as a novel immunohistochemical stain for trephine core biopsies of human bone marrow. We assessed the expression of IRF8 in 90 cases of AMoL, including posttherapy staging bone marrows, 23 cases of chronic myelomonocytic leukemia, 26 cases of other acute myeloid leukemia subtypes, and 18 normal control marrows. In AMoL, there was high correlation of IRF8-positive cells to aspirate blast count (R=0.95). Comparison of IRF8 staining to aspirate blast percentage in chronic myelomonocytic leukemia also showed good correlation (R=0.86). In contrast, IRF8-positi...
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

Cutaneous Lymphadenoma Is a Distinct Trichoblastoma-like Lymphoepithelial Tumor With Diffuse Androgen Receptor Immunoreactivity, Notch1 Ligand in Reed-Sternberg–like Cells, and Common EGFR Somatic Mutations
The term “cutaneous lymphadenoma” was coined in this journal for an unusual lymphoepithelial cutaneous adnexal neoplasm, possibly with immature pilosebaceous differentiation. Some authors further proposed that cutaneous lymphadenoma was an adamantinoid trichoblastoma. However, although a hair follicle differentiation is widely accepted, the fact that this is a lymphoepithelial tumor is not appropriately explained by the trichoblastoma hypothesis. Our goal was to further clarify the phenotypic and genotypic features of cutaneous lymphadenoma in a series of 11 cases. Histologically, a lobular architecture surroun...
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

Gastric Intestinal Metaplasia in Mucosa Adjacent to Gastric Cancers Is Rarely Associated With the Aneuploidy That Is Characteristic of Gastric Dysplasia or Cancer
In conclusion, the vast majority of the GIM samples (98%) lack the aneuploidy that is characteristic of gastric dysplasia or cancer. This indicates that aneuploidy usually occurs after the development of gastric dysplasia rather than at the stage of GIM. The finding also suggests that the presence of GIM alone may not be sufficient to suggest an increased risk for GC and that the inclusion of other high-risk features (ie, extensive GIM, dysplasia, racial minorities, and/or family history of GC in a first-degree relative) and/or aneuploidy ought to play a role in the selection of GIM patients who may warrant endoscopic surv...
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

Towards a More Standardized Approach to Pathologic Reporting of Pancreatoduodenectomy Specimens for Pancreatic Ductal Adenocarcinoma: Cross-continental and Cross-specialty Survey From the Pancreatobiliary Pathology Society Grossing Working Group
In conclusion, this survey raises the awareness of the discordances and serves as a starting point towards further standardization of the pancreatoduodenectomy grossing and reporting protocols. (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

Deep Herpes
This study presents the first known report of the ability of herpes virus to infect deep stromal cells of the dermis. We raise awareness of cutaneous stromal herpes in patients presenting with atypical clinical lesions, particularly while immunocompromised. Establishing the correct diagnosis is critical for initiating therapy. (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

The CERTAIN Study Results: Adjunctive p16 Immunohistochemistry Use in Cervical Biopsies According to LAST Criteria
The Lower Anogenital Squamous Terminology (LAST) Project recommends the use of p16 immunohistochemistry as an adjunct to morphologic assessment of cervical biopsies according to a specific set of criteria. We analyzed the effect of adjunctive p16 according to LAST criteria in a US-based diagnostic utility study involving 70 surgical pathologists providing a total of 38,500 reads on cervical biopsies. Compared with the results obtained using hematoxylin and eosin-stained slides only, including p16-stained slides per LAST criteria increased sensitivity and specificity for diagnosing histologic high-grade squamous intraepithe...
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

Salivary Mucinous Adenocarcinoma Is a Histologically Diverse Single Entity With Recurrent AKT1 E17K Mutations: Clinicopathologic and Molecular Characterization With Proposal for a Unified Classification
Mucin-producing salivary adenocarcinomas were historically divided into separate colloid carcinoma, papillary cystadenocarcinoma, and signet ring cell carcinoma diagnoses based on histologic pattern, but have recently been grouped together in the adenocarcinoma not otherwise specified category. It is currently unclear if these tumors represent 1 or more distinct entities and how they are related to well-circumscribed papillary mucinous lesions with recurrent AKT1 E17K mutations that were recently described as salivary intraductal papillary mucinous neoplasm. Here, we sought to evaluate the clinicopathologic and molecular f...
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

High-grade Follicular Lymphomas Exhibit Clinicopathologic, Cytogenetic, and Molecular Diversity Extending Beyond Grades 3A and 3B
Although follicular lymphoma (FL) is usually graded as FL1-2, FL3A, and FL3B, some borderline cases can be observed and led us to investigate the clinicopathologic diversity of grade 3 FL (FL3). Among 2449 FL patients enrolled in Lymphoma Study Association (LYSA) trials, 1921 cases with sufficient material underwent a central pathologic review. The resulting diagnoses comprised 89.6% FL1-2 (n=1723), 7.2% FL3A (n=138), and 0.5% purely follicular FL3B (n=9). The remaining 51 unclassifiable cases (2.7%) exhibited high-grade features but did not meet WHO criteria for either FL3A or FL3B; and were considered as “unconvent...
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

Fibrohistiocytic Variant of Hepatic Pseudotumor: An Antibiotic Responsive Tumefactive Lesion
Inflammatory pseudotumor is a term used to designate inflammation-rich tumefactive lesions. Following the exclusion of specific entities such as IgG4-related disease and other neoplastic entities previously included in this entity, the majority of hepatic pseudotumors show a prominent fibrohistiocytic inflammatory reaction and have been previously categorized as fibrohistiocytic variant of hepatic pseudotumor (FHVHPT). The goal of this study was to examine the clinical, radiologic, histologic, and etiologic aspects of this entity. After excluding neoplastic diseases, we identified 30 patients with FHVHPT from 3 institution...
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

Immunohistochemical Characterization of 120 Testicular Sex Cord-Stromal Tumors With an Emphasis on the Diagnostic Utility of SOX9, FOXL2, and SF-1
Sex cord-stromal tumors (SCSTs) account for the second most common category of testicular neoplasms and include several entities that may show overlapping morphologies and present diagnostic challenges. We analyzed a cohort of 120 testicular SCSTs and investigated the diagnostic utility of SRY-box transcription factor 9 (SOX9), forkhead box protein L2 (FOXL2), and steroidogenic factor 1 (SF-1) immunohistochemical stains. The results were compared with the more commonly used SCST markers, inhibin α, calretinin, and Wilms’ tumor 1 (WT1). SF-1 was overall the most sensitive stain (91%), followed by inhibin α...
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Original Articles Source Type: research

“Embryonic-type Neuroectodermal Tumor” Should Replace “Primitive Neuroectodermal Tumor” of the Testis and Gynecologic Tract: A Rationale for New Nomenclature
No abstract available (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - September 19, 2021 Category: Pathology Tags: Editorial Source Type: research

Response To: PD-1 and PD-L1 Immunohistochemistry as a Diagnostic Tool for Classic Hodgkin Lymphoma in Small-volume Biopsies
No abstract available (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Letters to the Editor Source Type: research

PD-1 and PD-L1 Immunohistochemistry as a Diagnostic Tool for Classic Hodgkin Lymphoma in Small-volume Biopsies
No abstract available (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Letters to the Editor Source Type: research

Atypical Pleomorphic Lipomatous Tumor: Expanding Our Current Understanding in a Clinicopathologic Analysis of 64 Cases
This study aims to further define the clinicopathologic features of APLT in a large series of 64 cases. Histologic features and ancillary studies were reviewed, and clinical and follow-up data were obtained from referring institutions. Immunohistochemistry for MDM2, CDK4, CD34, Rb, S100, and desmin was performed in cases with available material. Patients were 24 females and 40 males, and the median age was 61 years (range, 20 to 89 y). Tumors arose in upper limb (33%), lower limb (31%), trunk (23%), head and neck (8%), breast (3%), and inguinal region (2%), with a median size of 5.4 cm (range, 1.5 to 14.5&thi...
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research

PD-L1 Expression in Metaplastic Breast Carcinoma Using the PD-L1 SP142 Assay and Concordance Among PD-L1 Immunohistochemical Assays
Immunotherapy for the treatment of programmed death-ligand 1 (PD-L1) positive locally advanced or metastatic triple negative breast cancer may benefit patients with metaplastic breast cancer (MpBC). Previous study of PD-L1 in MpBC scored tumor cells (TCs), different from Food and Drug Administration-approved scoring methods. We sought to define PD-L1 expression in MpBCs and to evaluate concordance of 3 PD-L1 assays. Primary, treatment naive MpBC treated at our Center from 1998 to 2019 were identified. PD-L1 expression was assessed using SP142, E1L3n, and 73-10. We evaluated PD-L1 expression on tumor infiltrating immune cel...
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research

Significance of Alpha-inhibin Expression in Pheochromocytomas and Paragangliomas
Alpha-inhibin expression has been reported in pheochromocytomas and paragangliomas (PPGLs). We analyzed alpha-inhibin immunohistochemistry in 77 PPGLs (37 pheochromocytomas [PCCs] and 40 paragangliomas) and correlated the results with catecholamine profile, tumor size, Ki-67 labeling index, succinate dehydrogenase B subunit and carbonic anhydrase IX (CAIX) staining, and genetic pathogenesis. PPGLs were classified as pseudohypoxic cluster 1 disease with documented VHL mutation or SDHx mutation or biochemical phenotype, whereas NF1-driven and RET-driven PPGLs and those with a mature secretory (adrenergic or mixed adrenergic ...
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research

Steatotic and Steatohepatitic Hepatocellular Carcinomas: Features in a Series With Predominantly Viral Etiology
Hepatocellular carcinomas (HCCs) with steatohepatitis and steatosis are reported with varying definitions and clinicopathologic features. We aimed to search the attributes of steatohepatitic hepatocellular carcinoma (SH-HCC) and steatotic-HCC in our series. A retrospective clinicopathologic analyses of 150 HCCs and immunostaining for C-reactive protein (CRP) and serum amyloid A (SAA) were performed. Tumors were reclassified as all SH-HCC, limited SH-HCC, typical SH-HCC (steatohepatitic features in>5%, 5% to 50%, and ≥50% of the tumor, respectively), steatotic-HCC, and classic HCC (C-HCC). Group comparisons were made ...
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research

Utility of SOX6 and DAB2 for the Diagnosis of Malignant Mesothelioma
The separation of malignant mesothelioma from non–small cell lung carcinomas can be a difficult problem. Sex-determining region Y box 6 (SOX6) and disabled homolog 2 (DAB2) have recently been proposed as sensitive/specific markers of mesothelial lineage, but have not yet been independently tested for utility in mesothelioma diagnosis. Using tissue microarrays containing mesotheliomas (epithelioid: n=40, sarcomatoid: n=23) and non–small cell lung carcinomas (adenocarcinoma: n=52, squamous cell carcinoma: n=57, large cell carcinoma: n=12) we evaluated the performance of SOX6 and DAB2 by themselves, in conjunction...
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research

Prevalence and Predictors of Bacterial Contamination in Excisional Lymph Node Biopsies: Implications for Diagnosis and Management
Routine tissue handling exposes lymph node specimens to microbial contamination that can confound microbiological culture results and interfere with diagnosis. The scope and impact of this problem remain poorly understood. We combined over 13 years of lymph node pathology, culture data, and patient records to define the prevalence, predisposing factors, microbiology, and clinical management of false-positive lymph node cultures at a large academic medical center. Nearly one third (31.9%) of 216 cultured lymph nodes yielded bacterial growth. Approximately 90% of positive bacterial cultures grew 1 of 2 common skin-resident t...
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research

Atypical Teratoid/Rhabdoid Tumor (AT/RT) With Molecular Features of Pleomorphic Xanthoastrocytoma
In conclusion, the possibility of AT/RT with molecular features of PXA needs to be taken into account and warrants molecular characterization of AT/RT especially in older children. Since treatments targeting mutated BRAF are available, identification of such cases may also have therapeutic consequences. (Source: The American Journal of Surgical Pathology)
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research

NUT Is a Specific Immunohistochemical Marker for the Diagnosis of YAP1-NUTM1-rearranged Cutaneous Poroid Neoplasms
YAP1-NUTM1 fusion transcripts have been recently reported in poroma and porocarcinoma. NUTM1 translocation can be screened by nuclear protein in testis (NUT) immunohistochemistry in various malignancies, but its diagnostic performance has not been thoroughly validated on a large cohort of cutaneous epithelial neoplasms. We have evaluated NUT immunohistochemical expression in a large cohort encompassing 835 cases of various cutaneous epidermal or adnexal epithelial neoplasms. NUT expression was specific to eccrine poromas and porocarcinoma, with 32% of cases showing NUT expression. All other cutaneous tumors tested lacked N...
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research

Human Leukocyte Antigen Class I Deficiency in Gastric Carcinoma: An Adaptive Immune Evasion Strategy Most Common in Microsatellite Instable Tumors
This study included 58 MSI, 44 EBV-positive, and 107 non-EBV non-MSI tumors for comparison. The frequency of HLA-I deficiency (≥1% tumor cells) was significantly higher in MSI tumors (52%) compared with EBV-positive tumors (23%) and the other tumors (28%). In contrast, PD-L1 expression levels were highest in EBV-positive tumors, followed by MSI tumors, with the lowest prevalence in the other tumors in both Tumor Proportion Score and Combined Positive Score. HLA-I deficiency was significantly more frequent in advanced tumors (pT2-4) than in early tumors (pT1) in MSI and non-EBV non-MSI subtypes. In addition, the degree o...
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research

Primary Cilia Are Preserved in Cellular Blue and Atypical Blue Nevi and Lost in Blue Nevus–like Melanoma
Distinguishing cellular blue nevi (CBNs) and atypical CBNs from blue nevus–like melanoma (BNLM) can be diagnostically challenging. Immunohistochemistry may inform the diagnosis in a subset of cases but is not always diagnostic. Further, ancillary molecular testing is expensive and often requires significant tissue to complete. Primary cilia are cell-surface organelles with roles in signal transduction pathways and have been shown to be preserved in conventional melanocytic nevi but lost in melanoma. Immunofluorescence staining of primary cilia can be performed using a single standard-thickness formalin-fixed paraffin...
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research

IDH2 R172 Mutations Across Poorly Differentiated Sinonasal Tract Malignancies: Forty Molecularly Homogenous and Histologically Variable Cases With Favorable Outcome
IDH2 R172 mutations occur in sinonasal undifferentiated carcinoma (SNUC), large-cell neuroendocrine carcinoma (LCNEC), sinonasal adenocarcinomas, and olfactory neuroblastoma (ONB). We performed a clinical, pathologic, and genetic/epigenetic analysis of a large IDH2-mutated sinonasal tumor cohort to explore their distinct features. A total 165 sinonasal/skull base tumors included 40 IDH2 mutants studied by light microscopy, immunohistochemistry, and genome-wide DNA methylation, and 125 IDH2 wild-type tumors used for comparison. Methylation profiles were analyzed by unsupervised hierarchical clustering, t-distributed stochas...
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research

Intraoperative Frozen Section Biopsy of Uterine Smooth Muscle Tumors: A Clinicopathologic Analysis of 112 Cases With Emphasis on Potential Diagnostic Pitfalls
Frozen sections of uterine smooth muscle tumors are infrequently required, and related diagnostic difficulties are seldom discussed. We analyzed the clinicopathologic features of 112 frozen sections of uterine smooth muscle tumors and determined the accuracy, reasons for deferrals, and causes of interpretational errors. Most patients (median age, 45 y) presented with pelvic mass symptoms (53%). The main reasons for a frozen section examination were an abnormal gross appearance including loss of the usual whorled pattern of leiomyoma (36 cases, 32.1%), and intraoperative discovery of an abnormal growth pattern and ex...
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research

ALK Rearrangements Characterize 2 Distinct Types of Salivary Gland Carcinomas: Clinicopathologic and Molecular Analysis of 4 Cases and Literature Review
The majority of salivary gland carcinomas are characterized by recurrent gene fusions that proved highly valuable diagnostically, but only rarely of therapeutic impact. Most of these fusion-positive carcinomas belong to the low-grade or intermediate-grade biological category. To date, only 5 cases of salivary gland carcinomas carrying an oncogenic ALK fusion have been reported in 4 recent studies, but their phenotypic spectrum and their nosological classification remain uncharacterized. We herein describe in detail the clinicopathologic and molecular features of 4 ALK–fusion-positive salivary carcinomas and review pr...
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research

Pheochromocytoma: A Clinicopathologic and Molecular Study of 390 Cases From a Single Center
Pheochromocytomas are rare neuroendocrine tumors arising from chromaffin cells in the adrenal medulla. They may occur sporadically or in the context of hereditary syndromes. All pheochromocytomas are considered to have malignant potential (defined as risk of metastasis, not local invasion). The use of grading systems with incorporated clinical and histopathologic parameters can help but not definitively predict the metastatic potential of pheochromocytomas. The recent discovery of susceptibility genes provided new insights into the pathogenesis and introduced additional approaches to estimate the metastatic risk of pheochr...
Source: The American Journal of Surgical Pathology - August 22, 2021 Category: Pathology Tags: Original Articles Source Type: research