INI‐1 (SMARCB1)–Deficient Undifferentiated Sinonasal Carcinoma: Novel Paradigm of Molecular Testing in the Diagnosis and Management of Sinonasal Malignancies

摘要

Sinonasal tumors consist of a group of rare heterogeneous malignancies, accounting for 3%–5% of all head and neck cancers. Although squamous cell carcinomas make up a significant portion of cancers arising in the sinonasal tract, there are a variety of aggressive tumor types that can present with a poorly differentiated morphology and continue to pose diagnostic challenges. Accurate classification of these unique malignancies has treatment implications for patients. Recent discoveries have allowed more detailed molecular characterization of subsets of these tumor types, and may lead to individualized treatments. INI‐1 (SMARCB1)–deficient sinonasal carcinoma is a recently identified subtype of sinonasal malignancy, which is characterized by deletion of the INI‐1 tumor suppressor gene. Loss of INI‐1 expression has emerged as an important diagnostic feature in several human malignancies including a subset of sinonasal carcinomas. In this article, we present a case of INI‐1 (SMARCB1)–deficient sinonasal carcinoma, provide an overview of recent advances in histological and molecular classification of sinonasal malignancies, and discuss challenges of caring for patients with these rare malignancies, as well as potential treatment implications.