SMARCB1 and nasal cavity and paranasal sinus carcinoma: Initially reported as rare alternative mechanism in a rare subset of SMARCB1-proficient sinonasal carcinomas [28], SMARCA4 inactivation has latter been recognized as a defining marker for a distinctive subset of aggressive sinonasal epithelial neoplasms characterized by similar morphology as SMARCA4-deficient malignancies in other organs.