Clinicopathological analysis of 10 cases of SWI/SNF deficient sinonasal carcinoma

SWI/SNF-deficient sinonasal carcinomas, characterized by the loss of a subunit of the SWI/SNF complex, are exceedingly rare in clinical practice. This study aimed to characterize the clinicopathological features and prognosis of these tumors. We retrospectively analyzed 10 cases of SWI/SNF-deficient sinonasal carcinoma, focusing on their clinical characteristics, morphological features, and immunophenotypes. The patients ranged in age from 33 to 76 years and included seven women and three men. The tumors were centered in the nasal cavity in six cases (6/10), whereas four arose in the paranasal sinuses. Nine cases were classified as SMARCB1-deficient carcinoma, and one as SMARCA4-deficient carcinoma. The morphological patterns were heterogeneous. SMARCB1-deficient carcinomas exhibited basaloid, rhabdoid, undifferentiated, and adenoid architectures, whereas the SMARCA4-deficient carcinoma showed basaloid morphology. Three patients developed recurrence, and two developed metastases. SWI/SNF-deficient sinonasal carcinomas represent a rare subset of solid tumors with diverse morphological presentations. This clinicopathological analysis of 10 cases presents a morphologically diverse single-institution cohort, supports previously described morphological patterns, and enriches the clinicopathological data on this rare entity.