Polypoid PEComa in the Rectum of a 15-year-old Girl

Abstract

PEComa of the gastrointestinal tract, composed of perivascular epithelioid cells with myomelanocytic differentiation, is rare with previous literature limited to 16 case reports. There is a marked female preponderance and approximately one-third of the cases occur in the pediatric age group. We report PEComa with lymph node involvement occurring in the rectum of a 15-year-old girl, treated by surgical resection and adjuvant chemotherapy. The patient is well at 9 months follow-up with neither radiologic nor endoscopic evidence of recurrence. We review the differential diagnosis of intestinal PEComa, which includes malignant melanoma, epithelioid gastrointestinal stromal tumors, clear cell sarcoma of soft parts, alveolar soft part sarcoma, leiomyosarcoma with HMB45 expression, and paraganglioma. Immunohistochemistry can rule out many of these morphologically similar tumors but differentiation from clear cell sarcoma may require reverse transcription-polymerase chain reaction. We discuss the determination of pathologic features indicative of malignancy in PEComa, which is complicated in the gastrointestinal tract due to the small number of cases, variability of pathologic features reported, and inconsistent reporting of outcome. All 4 tumors reporting early recurrence or progression were greater than 5 cm in size and had areas of coagulative tumor necrosis. In addition, high nuclear grade and lymphovascular invasion were seen in 2 of these 4 cases. We propose that a minimum dataset for gastrointestinal PEComa should include these features along with mitotic count, infiltrative border, and tumor stage analogous to that used in colorectal carcinoma.

Perivascular epithelioid cell tumor (PEComa) of the ascending colon: the implication of IFN-α2b treatment

“…To our knowledge, 17 cases of GI PEComas have been reported in the literature, among which 10 occurred in adults3). Pediatric GI PEComas were documented in rectum3, 7, 8), appendix9), duodenum10), sigmoid colon11) and transverse colon12). This report is the eighth documented case of the pediatric GI PEComa, and the third documented case of the pediatric colon PEComa.…”

“…In the pediatric population, there have been only a few documented PEComas in several organs including the duodenum, appendix, transverse colon, sigmoid colon, rectum, kidney, broad ligament, vagina and orbit. To our knowledge, 17 cases of GI PEComas have been reported in the literature, among which 10 occurred in adults3). Pediatric GI PEComas were documented in rectum3, 7, 8), appendix9), duodenum10), sigmoid colon11) and transverse colon12).…”

“…Among 7 pediatric GI PEComa cases reported so far, six were treated with surgery alone7-12), and the last was treated with surgery and adjuvant chemotherapy consisting of doxorubicin, ifosfamide, and mesna on the basis of non-rhabdomyosarcoma soft tissue sarcoma protocol ARST0332 by Children's Oncology Group3).…”

“…Data on gastrointestinal (GI) PEComa remain limited to isolated case reports. To our knowledge, 17 cases have been reported in the literature, among which 10 occurred in adults3). Because of the rarity of PEComa, its clinical, phenotypic and biological characteristics are not fully understood, and little is known about prognosis and treatment modalities for PEComa.…”

Perivascular Epithelioid Cell Tumor of the Ileum Presenting as Diverticulitis

“…PEComa have been reported at diverse anatomic sites, including uterus, ligamentum teres, broad ligament, vagina, vulva, large and small bowel, pelvic side wall, thigh, heart, pancreas, kidney, skins and soft tissues [1, 4–6]. Gastrointestinal PEComas are exceptionally rare, there being only a few case reports in the literature involving the colon and small intestine.…”