Malignant Perivascular Epithelioid Cell Tumor Research Articles

Malignant Perivascular Epithelioid Cell Tumor (PEComa) of the Uterus

Abstract: This is a case of a 52-year-old woman who underwent a hyster-ectomy to treat a large uterine perivascular epithelioid cell tumor. She wasfollowed with serial F-18 FDG PET/CT scans due to positive surgicalmargins and vascular invasion on pathology. Initial surveillance PET/CTperformed 6 months post surgery was negative; however, a second surveil-lance PET/CT performed 12 months post surgery showed an intenselyFDG-avid recurrence in the pelvic surgical site. The patient received localradiotherapy, 2 cycles of taxol and carboplatin, and was placed on imatinibmesylate (Gleevec). A final PET/CT performed 6 months after initiation oftherapy showed rapidly disseminating metastatic disease and the patient died1 month later. This rare report highlights a potentially new utility of F-18FDG PET/CT for surveillance of recurrence of a malignant uterine perivas-cular epithelioid cell tumor, as well as for evaluation of response to therapy. Key Words: malignant perivascular epithelioid cell tumor, PEComa,uterus tumors, FDG, PET/CT(

Heterologous and Rare Homologous Sarcomas of the Uterine Corpus

Pure sarcomas of the uterine corpus are uncommon, constituting less than 3% of all malignancies at this site, and most of them are leiomyosarcomas and endometrial stromal sarcomas. Rare histotypes of homologous sarcomas and heterologous sarcomas are occasionally encountered, and the absence of significant accumulated experience with these histotypes at this location may potentially raise diagnostic and patient management difficulties. In this article, the clinicopathologic attributes of all earlier reported sarcomas of the uterine corpus other than leiomyosarcomas and endometrial stromal sarcomas are summarized. Included are embryonal rhabdomyosarcoma, pleomorphic rhabdomyosarcoma, angiosarcoma, alveolar soft part sarcoma, malignant perivascular epithelioid cell tumors (PEComas), osteosarcoma, chondrosarcoma, liposarcomatous tumors, malignant extrarenal rhabdoid tumors, Ewing sarcoma/primitive neuroectodermal tumor, and other rare histotypes. Embryonal rhabdomyosarcoma (20%), Ewing sarcoma/primitive neuroectodermal tumor (17%), angiosarcoma (14%), and pleomorphic rhabdomyosarcoma (13%) appeared to be more common than the others, although there was no single overwhelmingly prevalent histotype in the group. A subset, including embryonal rhabdomyosarcoma, alveolar soft part sarcoma, and PEComas, peak in the premenopausal years, but most of the others were observed in postmenopausal women. Favorable outcomes have been reported for the patients diagnosed with alveolar soft part sarcoma, and the prognosis for their counterparts with PEComa remains a matter of debate. Multimodal therapeutic approaches to contemporary patients with embryonal rhabdomyosarcomas have resulted in significantly improved outcomes. Unfortunately, most of the other sarcomas have been associated with rapid tumor progression and unfavorable patient outcomes. The differential diagnosis for these sarcomas is often extensive and varies by histotype, but their accurate diagnosis fundamentally requires the careful exclusion of biphasic malignancies.

An Unresectable Malignant Perivascular Epithelioid Cell Tumor Resistant to Multiple Combined Chemotherapies

Malignant perivascular epithelioid cell tumor (PEComa) was a kind of rare disease with malignant behavior and poor prognosis. Nearly all PEComas show immunoactivity for HMB45. The treatment strategy for malignant PEComa is still of controversy, especially in advanced or unresectable disease. We reported a 14-year-old patient of unresectable malignant PEComa, who was treated with multiple combined chemotherapies. The patient died of tumor 9 months after surgery, although 3 different combined chemotherapeutic regimens and antiangiogenic drug were used. Our case suggested that empirical chemotherapeutic regimens for soft tissue sarcomas might not be suitable for PEComa.

Clinical Activity of mTOR Inhibition With Sirolimus in Malignant Perivascular Epithelioid Cell Tumors: Targeting the Pathogenic Activation of mTORC1 in Tumors

PURPOSE Perivascular epithelioid cell tumors (PEComas) represent a family of mesenchymal neoplasms, mechanistically linked through activation of the mTOR signaling pathway. There is no known effective therapy for PEComa, and the molecular pathophysiology of aberrant mTOR signaling provided us with a scientific rationale to target this pathway therapeutically. On this mechanistic basis, we treated three consecutive patients with metastatic PEComa with an oral mTOR inhibitor, sirolimus. PATIENTS AND METHODS Patients with advanced PEComa were treated with sirolimus and consented to retrospective collection of data from their medical records and analysis of archival tumor specimens. Tumor response was determined by computed tomography scans obtained at the clinical discretion of the treating physicians. Tumors were assessed for immunohistochemical evidence of mTORC1 activation and genetic evidence of alterations in TSC1 and TSC2. Results Radiographic responses to sirolimus were observed in all patients. PEComas demonstrated loss of TSC2 protein expression and evidence of baseline mTORC1 activation. Homozygous loss of TSC1 was identified in one PEComa. CONCLUSION Inhibition of mTORC1, pathologically activated by loss of the TSC1/TSC2 tumor suppressor complex, is a rational mechanistic target for therapy in PEComas. The clinical activity of sirolimus in PEComa additionally strengthens the pathobiologic similarities linking PEComas to other neoplasms related to the tuberous sclerosis complex.

Malignant perivascular epithelioid cell tumor (‘PEComa’): a case report and literature review of cutaneous/subcutaneous presentations

Perivascular epithelioid cell (PEC) tumors, also called 'PEComas,' are distinct tumors showing PEC differentiation with characteristic histologic and immunophenotypic features. PEComas are rare tumors documented in the literature presenting in numerous anatomic sites including the thorax, abdomen, pelvis, soft tissue and skin. Criteria for malignancy does not exist for the subset of PEComas that pursue an aggressive clinical course. Herein, we present an unusual case of a malignant PEC tumor presenting as a scalp nodule in a patient with a prior diagnosis of 'melanoma' based upon the immunophenotypic profile of an excised enlarged cervical lymph node. The purpose of this case presentation is to further describe the rare clinical manifestations of a subcutaneous PEC tumor, emphasize the malignant potential of this entity, and review the literature focusing upon clinicopathologic features of cutaneous/subcutaneous PEComas.

Malignant perivascular epithelioid cell tumor (PEComa) of the uterus with late renal and pulmonary metastases: a case report with review of the literature

BackgroundPerivascular epithelioid cell tumor (PEComa), other than angiomyolipoma (AML), clear cell sugar tumor (CCST), and lymphangioleiomyomatosis (LAM), is a very rare mesenchymal tumor with an unpredictable natural history. The uterus is the most prevalent reported site of involvement of PEComa-not otherwise specified (PEComa-NOS). To the best of our knowledge, about 100 PEComa-NOS have been reported in the English Language medical literature, of which 38 were uterine PEComa-NOS. These reported cases of uterine PEComa-NOS have usually shown clinically benign behavior, but 13 tumors, three of them associated with tuberous sclerosis complex (TSC), exhibited local aggressive behavior and four of them showed distant metastases.Case presentationWe report the case of a 59-year-old woman, who presented with renal and pulmonary lesions seven years after the initial diagnosis of uterine leiomyosarcoma. Left nephrectomy and right middle lobe wedge resection were performed. Histological and immunohistochemical analysis of the renal and pulmonary lesions, in addition to retrospective re-evaluation of the previous uterine tumor, led to the final diagnosis of malignant uterine PEComa with late renal and pulmonary metastases. All three lesions had the typical histological appearance of PEComa-NOS showing a biphasic growth pattern with continuous transition between spindle cells and epithelioid cells, often arranged around vascular spaces. Immunohistochemically, the tumor cells of both phenotypes in all three lesions stained for melanocytic (HMB-45 and Melan-A/MART-1) and myoid (desmin, smooth muscle actin, and muscle-specific actin/all muscle actin/HHF-35) markers.ConclusionThe findings indicate that despite the small number of reported cases, PEComas-NOS should be considered tumors of uncertain malignant potential, and metastases to other organs might become evident even several years after the primary diagnosis.

Malignant perivascular epithelioid cell tumor of the colon: Report of a case with molecular analysis

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal neoplasm, and malignant cases are extremely rare. A case of malignant PEComa arising in the colon is described herein. The patient was a 43-year-old Japanese woman without a history of tuberous sclerosis complex. The tumor occurred in the abdominal cavity attached to the serosal side of the descending colon. Histologically, the tumor consisted of sheets or closely packed nests of epithelioid cells with clear or eosinophilic cytoplasms. The tumor cells were positive for HMB-45 but negative for S-100 protein and cytokeratins by immunohistochemical staining. Ki-67 labeling index was 2.9%. Peritoneal dissemination of tumor occurred at 20 months and the patient died of tumor at 38 months after the initial operation. This was considered to be a case of malignant PEComa, based on the histological and clinical features. Tumor cells showed overexpression of cyclin D1 but lacked the loss of heterozygosity of the TSC1 and TSC2 genes. The result suggests that the overexpression of cyclin D1 may play an important role in the tumorigenesis of PEComa. Because PEComas can behave in an aggressive manner, careful follow up is warranted.

Malignant perivascular epithelioid cell tumor (PEComa) arising in the broad ligament

Malignant perivascular epithelioid cell tumor (PEComa) is an extremely rare mesenchymal neoplasm mostly composed of HMB-45-positive epithelioid cells with clear-to-eosinophilic cytoplasm, a propensity for perivascular distribution and a coexpression of smooth muscle markers. The uterus seems to be one of the most prevalent sites of involvement, although only 14 cases of uterine PEComa have been described. We report the case of a 51-year-old woman with a PEComa arising in the broad ligament. She was treated with total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and pelvic radiation, and remains without evidence of disease 15 months after diagnosis. This is, to the best of our knowledge, the first report of a malignant PEComa arising in the broad ligament. To correctly diagnose PEComa, an extensive immunohistochemical panel is essential. As PEComas can behave in an aggressive manner, careful follow-up is warranted.