Perivascular epithelioid cell tumors (PEComa) of the gynecologic tract

Abstract

PEComas of the female genital tract are rare mesenchymal neoplasms that are most common in the uterus, but also may occur in other gynecologic locations. As they morphologically and immunohistochemically resemble smooth muscle tumors, distinction between the two entities is often challenging, and may be aided by molecular analysis. Thus far, two distinct molecular groups‐classic PEComas with TSC mutations and TFE3‐translocation associated PEComas with TFE3 fusions have been described. Recognition of the first group is imperative as these patients may benefit from targeted therapy with mTOR inhibitors, if malignant. This review will focus on recognition of the morphologic and immunophenotypic features of PEComas, as well as the role of molecular testing in their diagnosis and treatment, analysis of the different algorithms to predict behavior, and differential diagnosis.

PEComa—A Rare Liver Tumor

“…Furthermore, TP53 mutations have been identified in 63% of the TSC2 mutated Pecomas. The patients of the first group (if diagnosed with malignant tumors) may benefit from targeted therapy with mTOR inhibitors [4,25]. RAD51B fusions and HTR4-ST3GAL1 fusion are other rearrangements found in PEComas [18,26].…”

Sporadic uterine Lymphangioleiomyomatosis (LAM): Report of a unique case arising in the lower uterine segment with short review

“…The diagnosis of LAM in our case was based on the presence of typical morphologic features with confirmatory immunohistochemical stains. The immunophenotype of LAM is different from the other tumors in the PEComa family ( Bennett and Oliva, 2021 ). HMB-45 is usually negative or only weak/patchy staining in LAM cells ( Rabban et al, 2015 ).…”

“…Moreover, melan-A has relatively low sensitivity and shows negative staining in most cases ( Rabban et al, 2015 ). Diffuse positivity for cathepsin K has been described to have more sensitivity for LAM cells, and it can be used as an alternative marker to melan-A ( Bennett and Oliva, 2021 , Lombard, 2020 ). With unusual IHC, recognition of characteristic morphologic features is the key in LAM diagnosis ( Rabban et al, 2015 ).…”

Perirenal Perivascular Epithelioid Cell Tumor (PEcoma) with Pulmonary Micro Invasive Adenocarcinoma: A Case Report and Literature Review

“…Immunohistochemistry plays a vital role in the diagnosis. According to a systematic review in 2020, 18 HMB45, a specific marker for PEComa, abundantly clear to eosinophilic granular cytoplasm, is 99% positive in PEComa and has been utilized to support the diagnosis of PEComa at multiple sites. 19 The positive rate of Melan-A, which is recognized as an antigen on melanoma cells by cytotoxic T-lymphocytes, varied from 13% to 88% in PEComa 18.…”