Cytopathologic characteristics of SMARCB1 (INI-1) deficient sinonasal carcinoma: A potential diagnostic pitfall

Derek B. Allison, Justin A. Bishop, Syed Z. Ali

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Tumors of the head and neck are extremely diverse and a subset are poorly differentiated and difficult to classify. Recently, a new entity has been described with rhabdoid and/or plasmacytoid cytologic features and a characteristic genetic signature—inactivation of the SMARCB1 (INI-1) tumor suppressor gene. To date, only 16 cases of SMARCB1 (INI-1) deficient sinonasal carcinoma have been described, and there are currently no reports of the cytopathologic features by fine needle aspiration (FNA) cytology. A case of a 77-year-old man who presented with a posterior ethmoid sinus lesion with invasion into the skull base and bone was reported. FNA cytology of a right retropharyngeal lymph node revealed relatively monomorphic, loosely cohesive clusters of plasmacytoid cells with occasional nucleoli, rare intranuclear cytoplasmic inclusions, and mitotic figures in a background of necrosis and absence of overt squamous or glandular differentiation. A diagnosis of metastatic myoepithelial carcinoma was made; however, retrospectively, the surgical excision showed loss of the SMARCB1 (INI-1) tumor suppressor gene by immunohistochemistry. In summary, the cytomorphologic features of SMARCB1 (INI-1) deficient sinonasal carcinoma are relatively nonspecific and overlap with other regional tumors, including myoepithelial neoplasms. As a result, this entity should be considered in the differential diagnosis for a plasmacytoid tumor arising in the sinonasal tract by FNA cytology. Diagn.

Original languageEnglish (US)
Pages (from-to)700-703
Number of pages4
JournalDiagnostic Cytopathology
Issue number8
StatePublished - Aug 1 2016


  • cytopathology
  • fine needle aspiration
  • sinonasal carcinoma
  • SMARCB1 (INI1)

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology


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