title: Uterine epithelioid leiomyosarcoma with c-kit expression and YWHAE gene rearrangement: a case report of a diagnostic pitfall of uterine sarcoma.
abstract: BACKGROUND
  Uterine sarcoma is a rare tumor that is often difficult to classify based on morphological and immunohistochemical analysis alone. Limited access to molecular biological analysis in routine practice would hinder making a definitive diagnosis.
  
  
  METHODS
  In this report, we describe a case of a mesenchymal tumor arising from the uterine cervix in a 52-year-old woman. From microscopic morphology of the resected specimen, epithelioid leiomyosarcoma, high-grade endometrial stromal sarcoma, or uterine gastrointestinal stromal tumor (GIST) were considered as differential diagnoses. The immunophenotype of the tumor featured smooth muscle differentiation and hormone receptor expression. The cell membrane and cytoplasm were positive for c-kit, although no mutation was found in the c-kit or PDGFRA gene. Fluorescence in situ hybridization (FISH) analysis revealed a relatively low frequency of YWHAE rearrangement, whereas there were few NUTM2A and NUTM2B split signals.
  
  
  CONCLUSIONS
  In this case, the tumor was not typical of any three of the differential diagnoses mentioned above. However, insufficient frequency of YWHAE, NUTM2A, and NUTM2B gene rearrangement and absence of mutation in both the c-kit and PDGFRA genes suggested that this tumor should be categorized as epithelioid leiomyosarcoma. This is an instructive case showing a potential diagnostic pitfall of uterine sarcoma. Comprehensive approaches including molecular biological techniques are required for definitive diagnosis.
authors.affiliation: Department of Surgical Pathology, School of Medicine, Sapporo Medical University, South 1, West 16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan.
authors.forename: Terufumi
authors.initials: T
authors.lastname: Kubo
authors.affiliation: Department of Surgical Pathology, School of Medicine, Sapporo Medical University, South 1, West 16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Sugita
authors.affiliation: Department of Integrated Diagnostic Pathology, Nippon Medical School, Tokyo, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Wada
authors.affiliation: Department of Surgical Pathology, School of Medicine, Sapporo Medical University, South 1, West 16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Kikuchi
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, Sapporo Medical University, Sapporo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Iwasaki
authors.affiliation: Department of Surgical Pathology, School of Medicine, Sapporo Medical University, South 1, West 16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan.
authors.forename: Yumika
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Department of Surgical Pathology, School of Medicine, Sapporo Medical University, South 1, West 16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Sugawara
authors.affiliation: Department of Surgical Pathology, School of Medicine, Sapporo Medical University, South 1, West 16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Fujita
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Sapporo Medical University, South 1, West 16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Emori
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, Sapporo Medical University, Sapporo, Japan.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Tanaka
authors.affiliation: Department of Surgical Pathology, School of Medicine, Sapporo Medical University, South 1, West 16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hirano
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, Sapporo Medical University, Sapporo, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Saito
authors.affiliation: Department of Surgical Pathology, School of Medicine, Sapporo Medical University, South 1, West 16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan. hasetada@sapmed.ac.jp.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Hasegawa
mesh_terms: D048948:14-3-3 Proteins / Q000235:genetics*; D014408:Biomarkers, Tumor / Q000032:analysis; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D007890:Leiomyosarcoma / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D008875:Middle Aged; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis*; D018203:Sarcoma, Endometrial Stromal / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D014594:Uterine Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology
chemical_list: D048948:14-3-3 Proteins; D014408:Biomarkers, Tumor; C482983:YWHAE protein, human; D019009:Proto-Oncogene Proteins c-kit
keywords: FISH; Uterine leiomyosarcoma; YWHAE rearrangement; c-kit