title: Nasopharyngeal hyalinizing clear cell carcinoma: report of the histopathologic features of a case showing EWSR1 rearrangements by FISH and literature review.
abstract: BACKGROUND
  Hyalinizing clear cell carcinoma (HCCC) is a rare low-grade malignant tumor affecting the minor salivary glands; nasopharyngeal involvement is uncommon.
  
  
  RESULTS
  A 38-year-old male patient presented with a 3.2 × 4.5 × 4.4 cm expansile mass obliterating the lumen of the nasopharynx and extending into the left nasal cavity. Histopathologically, the tumor was characterized by clear round to polygonal epithelial cells arranged in anastomosing trabeculae and solid nests. The stroma consisted of fibromyxoid connective tissue with areas of intense hyalinization and desmoplasia. Immunohistochemically, strong and diffuse reactivity for AE1/AE3, CK5/6, and p63 was observed. EWSR1 gene rearrangement was confirmed by fluorescence in situ hybridization. The diagnosis of nasopharyngeal HCCC was rendered. Surgical excision was performed along with adjuvant radiotherapy and chemotherapy.
  
  
  CONCLUSIONS
  HCCC generally demonstrates good prognosis with low metastatic potential. Identification of EWSR1 gene disruption is usefulin discerning HCCC from other neoplasms with overlapping microscopic features.
authors.affiliation: National Autonomous University of Mexico, Mexico City, Mexico.
authors.forename: Celina
authors.initials: C
authors.lastname: Ceballos Sáenz
authors.affiliation: University of Minnesota, Minneapolis, MN, USA.
authors.forename: Prokopios P
authors.initials: PP
authors.lastname: Argyris
authors.affiliation: Veterans Administration Medical Center, Minneapolis, MN, USA.
authors.forename: J Carlos
authors.initials: JC
authors.lastname: Manivel
authors.affiliation: National Autonomous University of Mexico, Mexico City, Mexico.
authors.forename: Cynthia Marina
authors.initials: CM
authors.lastname: Urias Barreras
authors.affiliation: University of Minnesota, Minneapolis, MN, USA koutl001@umn.edu.
authors.forename: Ioannis G
authors.initials: IG
authors.lastname: Koutlas
mesh_terms: D018262:Adenocarcinoma, Clear Cell / Q000235:genetics* / Q000473:pathology*; D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D002148:Calmodulin-Binding Proteins / Q000235:genetics*; D002277:Carcinoma; D015321:Gene Rearrangement; D006801:Humans; D006818:Hyalin / Q000378:metabolism; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000235:genetics* / Q000473:pathology*; D034802:RNA-Binding Protein EWS; D016601:RNA-Binding Proteins / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; D002148:Calmodulin-Binding Proteins; C500986:EWSR1 protein, human; D034802:RNA-Binding Protein EWS; D016601:RNA-Binding Proteins
keywords: EWSR1 rearrangement; FISH; hyalinizing clear cell carcinoma; immunohistochemistry; nasopharynx