Perivascular epithelioid cell tumors (PEComa) of the female genital tract: A challenging question for gynaecologic oncologist and pathologist

Abstract

Perivascular epithelioid cell tumors (PEComa)s are mesenchymal neoplasms composed of perivascular epithelioid cells, which express both melanocytic and myogenic markers. These neoplastic cells are thought to arise from undifferentiated cells of the neural crest, or from myoblastic cells harbouring a molecular alteration leading to expression of melanocytic markers, or from pericytic cells. The majority of cases are benign, but a small subset behaves in a malignant fashion. Unfortunately, given their rarity, reliable criteria for predicting malignancy have yet to be established. PEComas of the female genital tract account for nearly 25% of PEComas of all body sites, and the most common site of occurrence is the uterine corpus; less common sites include the cervix, adnexa, vagina/vulva or broad or round ligament exceptionally. The present review aims to elucidate the clinical, pathological and molecular features of gynecological PEComas. Moreover, prognostic and therapeutic implications are also discussed.

Keywords: Cervical PEComas; Melanocytic markers; Myogenic markers; Ovarian PEComas; Uterine perivascular epithelioid cell tumors (PEComas).

Fig. 1

Haematoxylin and eosin (H&E) stained sections illustrating the histopathological features of uterine PEComa A). Neoplastic cells are arranged in nested pattern and show abundant clear and granular cytoplasm with small, round to oval nuclei and small nucleoli. B). This tumor exhibits a useful diagnostic clue: neoplastic cells are arranged around a vascular space (arrow). C). Diffuse immunohistochemical expression for MELAN-A is depicted.

Fig. 2

Haematoxylin and eosin (H&E) stained sections illustrating the histopathological features of malignant uterine PEComa. A). The present case showed infiltrative growth pattern and extensive lympho-vasular invasion (arrows). B). This tumor also exhibited significant cytological atypia and increased mitotic activity also with atypical mitotic figures (arrow). C). Immunohistochemical expression for HMB-45 is depicted. D). Neoplastic cells were also positive for MELAN-A.