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Cytopathologic characteristics of SMARCB1 (INI‐1) deficient sinonasal carcinoma: A potential diagnostic pitfall
Author(s) -
Allison Derek B.,
Bishop Justin A.,
Ali Syed Z.
Publication year - 2016
Publication title -
diagnostic cytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.417
H-Index - 65
eISSN - 1097-0339
pISSN - 8755-1039
DOI - 10.1002/dc.23503
Subject(s) - smarcb1 , medicine , pathology , fine needle aspiration , cytopathology , myoepithelial cell , differential diagnosis , immunohistochemistry , biopsy , cytology , biology , gene , biochemistry , chromatin remodeling , chromatin
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. Cytopathol. 2016;44:700–703. © 2016 Wiley Periodicals, Inc.