title: Myoepithelioma-like Tumors of the Vulvar Region: A Distinctive Group of SMARCB1-deficient Neoplasms.
abstract: We describe 9 tumors that resemble soft tissue myoepitheliomas but possess certain traits that do not fit perfectly into this category. These tumors, herein referred to as "myoepithelioma-like tumors of the vulvar region," occurred in the subcutis of the vulva and surrounding regions of adult women aged 24 to 65 years. Histologically, the tumors measured 2 to 7.7 cm and were well circumscribed, focally encapsulated, and lobulated. Tumor cells had an epithelioid to spindled shape, with fine amphophilic cytoplasm, and uniform nuclei with vesicular chromatin and nucleoli. The tumor stroma was relatively hypervascular, and comprised a mixture of myxoid and nonmyxoid components. Myxoid areas accounted for <5% to 95% of the tumor volume, wherein cells proliferated singly or in a loosely cohesive manner. In nonmyxoid areas, tumors cells grew in diffuse sheets or storiform arrangements. Immunohistochemically, all tested tumors were positive for vimentin, epithelial membrane antigen, and estrogen receptor; most tumors expressed actin. All tumors were negative for S100 protein, glial fibrillary acidic protein, and CD34. Cytokeratin expression was absent in all but 2 tumors, which showed rare positivity. SMARCB1 expression was deficient in all cases. EWSR1, FUS, and NR4A3 rearrangements were absent. All tumors were treated through surgery. Although 3 tumors regrew or recurred after intralesional excision, all 9 patients were alive without metastases at a mean follow-up of 66 months. Myoepithelioma-like tumors of the vulvar region constitute a distinct group of tumors, although future research is required to determine whether they are an unusual subtype of soft tissue myoepitheliomas or a separate disease.
authors.affiliation: Departments of *Pathology and Clinical Laboratories †Musculoskeletal Oncology ∥Gynecology, National Cancer Center Hospital Departments of ‡Gynecology ††Pathology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital §Department of Obstetrics and Gynecology, Graduate School of Medicine #Department of Pathology, University of Tokyo, Tokyo ¶Department of Pathology, Kawasaki Municipal Hospital, Kanagawa **Department of Cellular and Organ Pathology, Akita University, Akita, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yoshida
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoshida
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yoshida
authors.forename: Taisuke
authors.initials: T
authors.lastname: Mori
authors.forename: Eisuke
authors.initials: E
authors.lastname: Kobayashi
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Tanzawa
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Yasugi
authors.forename: Kei
authors.initials: K
authors.lastname: Kawana
authors.forename: Mitsuya
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sugiura
authors.forename: Daichi
authors.initials: D
authors.lastname: Maeda
authors.forename: Masashi
authors.initials: M
authors.lastname: Fukayama
authors.forename: Akira
authors.initials: A
authors.lastname: Kawai
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Hiraoka
authors.forename: Toru
authors.initials: T
authors.lastname: Motoi
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000172:deficiency* / Q000235:genetics; D001706:Biopsy; D049109:Cell Proliferation; D002868:Chromosomal Proteins, Non-Histone / Q000172:deficiency*; D004268:DNA-Binding Proteins / Q000172:deficiency*; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008875:Middle Aged; D009208:Myoepithelioma / Q000737:chemistry* / Q000145:classification / Q000235:genetics / Q000473:pathology / Q000601:surgery; D011237:Predictive Value of Tests; D000071796:SMARCB1 Protein; D013997:Time Factors; D014157:Transcription Factors / Q000172:deficiency*; D016896:Treatment Outcome; D047368:Tumor Burden; D014846:Vulvar Neoplasms / Q000737:chemistry* / Q000145:classification / Q000235:genetics / Q000473:pathology / Q000601:surgery; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors