Histological classification of mucinous ovarian tumors: inter-observer reproducibility, clinical relevance, and role of genetic biomarkers

AbstractThe morphological distinction between the various types of mucinous ovarian tumors has major prognostic implications but may be challenging. The aims of our study were to describe inter-observer reproducibility in the morphological diagnosis of mucinous ovarian tumors, to evaluate the clinical relevance of possible diagnostic discrepancies, and to identify molecular abnormalities correlated with the histological type. Seventy-nine ovarian mucinous borderline tumors (MOB) and either expansile or infiltrative carcinomas (MOC) were independently reviewed by two gynecological pathologists. Molecular analysis was performed in 32 cases. Concordance between the two pathologists was reached in 67 cases (k: 0.78). The main discrepancies (8/12) were the evaluation of nuclear grade 3 or that of microfoci (<  5 mm) of infiltrative-type carcinoma in an otherwise typical expansile MOC. Our follow-up analysis showed that infiltrative MOC had a lower overall survival (OS) (p <  0.0024) and progression-free survival (PFS) (p = 0.0060) as compared with MOB and expansile MOC. The presence of nuclear grade 3 or microfoci (<  5 mm) of infiltrative-type pattern of invasion in an otherwise typical expansile MOC did not alter the prognosis as compared with expansile MOC without these features, in terms of OS (p <  0.0028) and PFS (p = 0.0074).KRAS mutations were more frequent in MOB (71%), than in expansile (50%) and infiltrative MOC (14%). In contrast, the ...

Source: Virchows Archiv - October 2, 2020 Category: Pathology Source Type: research