title: Primary clear cell sarcoma of the tongue.
abstract: Clear cell sarcoma shares features with melanoma, but frequently shows EWSR1 rearrangements. It is an aggressive tumor typically occurring in the soft tissues of the extremities, with a gastrointestinal variant with less consistent melanocytic differentiation. It is extremely rare in the head and neck region, with no reported cases in the oral cavity. We report a case of an 82-year-old woman with a clear cell sarcoma arising in the tongue, with cervical lymph node metastases. Histologically, the tumor showed some features of gastrointestinal clear cell sarcoma. No osteoclast-type giant cells were present. The tumor cells were positive for S100 protein and negative for other melanocytic markers. Fluorescence in situ hybridization showed rearrangements of EWSR1 and ATF1. This case expands the spectrum of clear cell sarcoma with a gastrointestinal-like variant in a novel site, emphasizing the need to consider it as a differential diagnosis to melanoma in mucosal sites.
authors.affiliation: From the Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston (Drs Kraft, Rosenberg, and Nielsen); the Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York (Dr Antonescu); and the Division of Head and Neck Surgery, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston (Dr Deschler).
authors.forename: Stefan
authors.initials: S
authors.lastname: Kraft
authors.forename: Cristina R
authors.initials: CR
authors.lastname: Antonescu
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Rosenberg
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Deschler
authors.forename: G Petur
authors.initials: GP
authors.lastname: Nielsen
mesh_terms: D051697:Activating Transcription Factor 1 / Q000235:genetics; D000368:Aged; D000369:Aged, 80 and over; D002148:Calmodulin-Binding Proteins / Q000235:genetics; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D034802:RNA-Binding Protein EWS; D016601:RNA-Binding Proteins / Q000235:genetics; D009418:S100 Proteins / Q000378:metabolism; D018227:Sarcoma, Clear Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D014062:Tongue Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*
chemical_list: C531110:ATF1 protein, human; D051697:Activating Transcription Factor 1; D002148:Calmodulin-Binding Proteins; C500986:EWSR1 protein, human; D034802:RNA-Binding Protein EWS; D016601:RNA-Binding Proteins; D009418:S100 Proteins