Uterine PEComa: appraisal of a controversial and increasingly reported mesenchymal neoplasm. Int Semin Surg Oncol 5:7

Department of Pathology, Wilford Hall Medical Center, Lackland Air Force Base, San Antonio, TX 78236, USA. .
International Seminars in Surgical Oncology 02/2008; 5(1):7. DOI: 10.1186/1477-7800-5-7
Source: PubMed


In recent years, a group of tumors that have been designated "perivascular epithelioid cell tumors" (PEComa) have been reported with increasing frequency from a wide variety of anatomic locations. The uterus and retroperitoneum appear to be the most frequent sites of origin for these lesions. PEComas belong to an identically named family of tumors comprised of conventional angiomyolipomas, clear cell sugar tumors, lymphangiomyomatosis and clear cell myomelanocytic tumor of the falciform ligament/ligament teres, and are also known as PEComa-NOS. This article is a primer for clinicians on the most salient clinicopathologic features of uterine PEComas, as most of the debate and discussion have taken place in the pathologic literature. The author appraises in detail the current state of knowledge on PEComas of the uterus based on a review of published data on the 44 previously reported cases, and comments on areas of controversy. The latter are centered predominantly on the significant morphologic and immunophenotypic overlap that exists between uterine PEComa and some smooth muscle tumors of the uterus. The clinicopathologic features of cases reported as epithelioid smooth muscle tumors and cases reported as uterine PEComas are compared and contrasted, and a practical approach to their reporting is proposed.

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    • "Regardless, the pathologist may need to perform melanocytic markers to distinguish them. From a clinical perspective, Fadare's review [12] noted that 13 of 37 (35%) cases with follow up information had evidence of metastasis either at diagnosis or at follow up. Thus the prognosis is similar to other PEComa NOS. "
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    ABSTRACT: Perivascular epithelioid tumors (PEComa) are uncommon mesenchymal neoplasms demonstrating positivity for muscular and melanocytic immuno-markers. Included in this category are angiomyolipoma, lymphangioleiomyomatosis, and clear cell sugar tumors. Lesions which do not fit into these categories are classified as "not otherwise specified". We present a case of an incidentally discovered PEComa within inguinal hernia sac contents in a 70-year-old woman. It consisted of spindled and epithelioid cells with bland oval nuclei, small nucleoli and clear to light eosinophilic cytoplasm. There was no atypia or mitoses. The lesion was strongly positive for HMB45 and smooth muscle actin. Pelvic soft tissue and peritoneal PEComas are rarely reported in literature and very little is known about their prognosis. We discuss the immunohistochemistry, differential diagnosis, and pathogenesis of PEComas.
    Full-text · Article · Jun 2013 · Pathology - Research and Practice
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    • "Uterine PEComas being a distinct clinicopathologic entity can be challenged by frequent HMB-45 expression in epithelioid and conventional leiomyosarcomas of the uterus [27-29]. The question arises as to whether uterine PEComas are a distinctive entity or whether they represent a subgroup of HMB-45-positive smooth muscle tumors [30]. Since smooth muscle tumors typically originate in the myometrium, the endometrial origin of early PEC lesions supports uterine PEComas being a distinctive tumor. "
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    ABSTRACT: Perivascular epithelioid cell (PEC) tumors (PEComas) are a family of related mesenchymal tumors composed of PECs which co-express melanocytic and smooth muscle markers. Although their distinctive histologic, immunohistochemical, ultrastructural, and genetic features have been clearly demonstrated, their histogenesis and normal counterpart remain largely unknown. Precursor lesions of PEComas have rarely been reported. We herein describe a tuberous sclerosis patient with microscopic PEC nodules in the endometrium of adenomyosis, pelvic endometriosis, an ovarian endometriotic cyst, and the endometrium of the uterine cavity. The nodules showed a mixture of spindle-shaped and epithelioid cells concentrically arranged around small arteries. The cells exhibited uniform nuclei, light eosinophilic cytoplasm, and immunoreactivity with HMB-45 and CD10. Some nodules revealed continuity with a PEComa in the myometrium. These findings support microscopic endometrial PEC nodules possibly being precursor lesions of uterine PEComas. The wide distribution of the nodules in the pelvis may be related to the multicentricity of PEComas in tuberous sclerosis patients. Owing to the immunoreactivity with CD10, microscopic endometrial PEC nodules may be misinterpreted as endothelial stromal cells unless melanocytic markers are stained. To the best of our knowledge, this is a case with the earliest manifestation of PEC lesions occurring in the endometrium. Virtual Slides The virtual slide(s) for this article can be found here:
    Full-text · Article · Sep 2012 · Diagnostic Pathology
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    • "PEComa are characterized by an epithelioid morphology, clear to eosinophilic granular cytoplasm, coexpression of smooth muscle (actin and/or desmin) and melanocytic markers (HMB-45 and/or melanA), and at least in some cases, arrangement around blood vessels.2,3 However, in our case tumor cells expressed HMB-45 strongly, but no smooth muscle markers. "
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    ABSTRACT: Perivascular epithelioid cell tumors (PEComa) are mesenchymal tumors composed of histologically and immunohistochemically distinctive perivascular epithelial cells. Although the uterine corpus seems to be one of the most prevalent sites of involvement, PEComa of the uterine cervix are very rare. Only four cervical PEComa cases have been described, and were treated with hysterectomy and radiotherapy. We report a case of a 24-year-old nulligravida woman who presented with acute abdominal pain and was diagnosed with a rupture of an ovarian chocolate cyst. Subsequent surgery revealed that the tumor arose in the uterus, and the histological diagnosis was uterine PEComa with low potential malignancy. Recurrent PEComa in the uterine cervix were excised twice, and she remains disease free 12 months after the last operation. To the best of our knowledge, this is the first report of recurrent cervical PEComa with fertility-preserving surgery. Estimating the malignant potential and appropriate surgery are essential for young patients with uterine PEComa.
    Full-text · Article · Apr 2010 · Rare tumors
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