Predicting the Behavior of Perivascular Epithelioid Cell Tumors of the Uterine Corpus

Abstract

Perivascular epithelioid cell tumors (PEComas) are rare neoplasms that share phenotypic features with angiomyolipomas, clear cell sugar tumors, and lymphangioleiomyomatosis. They presumably represent the neoplastic counterpart of a yet-unidentified perivascular epithelioid cell that expresses smooth muscle and melanocytic immunomarkers. The uterus is the second most common site of origin for perivascular epithelioid cell tumors, after the retroperitoneum. Although most uterine perivascular epithelioid cell tumors are clinically benign and can be cured by a complete surgical excision, there is a subset characterized by both local and distant dissemination. Unfortunately, no single histopathologic or immunohistochemical parameter can accurately predict the clinical behavior of these tumors, which is why the 2012 World Health Organization classification of tumors of the female reproductive organs suggests the use of several criteria to predict the risk of aggressive clinical behavior. Here we review those perivascular epithelioid cell tumors of the uterine corpus with aggressive clinical behavior reported in the literature, and we discuss their most relevant clinical and histopathologic features.

Pneumothorax caused by cystic and nodular lung metastases from a malignant uterine perivascular epithelioid cell tumor (PEComa)

“…No narrative citing such patients who developed a pneumothorax is available in the literature. Acosta AM and Adely BP recently reviewed 16 reports of clinically aggressive PEComas of the uterine corpus (CAPUs) comprising a total of 20 patients: half of them had lung metastases, all had radiologically evident nodules, but none had the complication of a pneumothorax [13]. Interestingly, but not an exception, one publication pertained to a patient whose acute presentation of a PEComa and a spontaneous uterine rupture resembled but did not duplicate our patient's situation [14].…”

“…Although several reports have appeared in which imaging [12] or clinical features [13] of uterine PEComas and pulmonary metastasis were cited, those accounts were limited to the imaging scans of pulmonary metastasis or discrete nodular lesions. No narrative citing such patients who developed a pneumothorax is available in the literature.…”

“…The pulmonary manifestations of CAPUs require clear differentiation from LAM, leiomyosarcoma and low-grade endometrial stromal sarcoma (ESS) [13]. We previously described a patient with ESS who showed cystic, nodular and cavitary lung metastases to the lungs and also the complication of a pneumothorax induced by tumor-cell infiltration of the visceral pleura [15].…”

Extrapulmonary uterine lymphangioleiomyomatosis (LAM) and dysfunctional uterine bleeding: the first presentation of LAM in a tuberous sclerosis complex patient

“…Despite the uterus being the second most common location for PEComas after the retroperitoneum,17 18 to the best of our knowledge, only 26 cases of uterine LAM have been reported in the literature 3 13 14 19–23. Its rarity, variable, sometimes vague presentation and morphology can often make diagnosing LAM challenging (please see tables 1 and 2 for differentials) 4 13 17 18 24–27…”

“…Uterine LAM is typically considered as a low-grade lesion6 8 14; however, a case of sarcomatous transformation has been described 28. The WHO recommends seven parameters to identify PEComas with potentially aggressive behaviour: these are size > 5 mm, high cellularity, nuclear atypia, mitotic activity > 1/50 hpfs, necrosis, infiltration and vascular invasion 18 29. Additionally, the modified-Folpe-Schoolmeester classification system can be used for prognostification 15.…”