Update on Sinonasal Tract Malignancies: Advances in Diagnostic Modalities.

Context.—: Sinonasal tract malignancies are rare cancers with frequent morphologic overlap. Given the similar histologic profiles seen in many of these entities, they often present a diagnostic challenge to the practicing pathologist.

Objective.—: To provide a streamlined algorithm using histologic clues, immunohistochemical profiles, and molecular assays to aid in diagnosis of these lesions.

Data Sources.—: Sources were the World Health Organization Tumor Classification, literature review, and institutional experience.

Conclusions.—: Although many sinonasal tract malignancies show similar histology, distinct immunohistochemical and molecular profiles can help parse out differences, thereby facilitating diagnosis for the pathologist.