title: Microscopic endometrial perivascular epithelioid cell nodules: a case report with the earliest presentation of a uterine perivascular epithelioid cell tumor.
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: http://www.diagnosticpathology.diagnomx.eu/vs/9658280017862643.
authors.affiliation: Department of Pathology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Chia-Lang
authors.initials: CL
authors.lastname: Fang
authors.forename: Yun-Ho
authors.initials: YH
authors.lastname: Lin
authors.forename: Wei-Yu
authors.initials: WY
authors.lastname: Chen
mesh_terms: D062788:Adenomyosis / Q000473:pathology; D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D055088:Early Detection of Cancer; D004715:Endometriosis / Q000473:pathology; D004717:Endometrium / Q000737:chemistry / Q000276:immunology / Q000473:pathology* / Q000601:surgery; D015622:Epithelioid Cells / Q000737:chemistry / Q000276:immunology / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D018192:Lymphangioleiomyomatosis / Q000473:pathology; D058950:Melanoma-Specific Antigens / Q000032:analysis; D015260:Neprilysin / Q000032:analysis; D010048:Ovarian Cysts / Q000473:pathology; D054973:Perivascular Epithelioid Cell Neoplasms / Q000737:chemistry / Q000276:immunology / Q000473:pathology* / Q000601:surgery; D011230:Precancerous Conditions / Q000737:chemistry / Q000276:immunology / Q000473:pathology* / Q000601:surgery; D011237:Predictive Value of Tests; D016896:Treatment Outcome; D014402:Tuberous Sclerosis / Q000276:immunology / Q000473:pathology* / Q000601:surgery; D014594:Uterine Neoplasms / Q000737:chemistry / Q000276:immunology / Q000473:pathology* / Q000601:surgery; D058951:gp100 Melanoma Antigen
chemical_list: D014408:Biomarkers, Tumor; D058950:Melanoma-Specific Antigens; C548637:PMEL protein, human; D058951:gp100 Melanoma Antigen; D015260:Neprilysin