Article Description: Sinonasal masses are uncommon and can be challenging to evaluate. Hemorrhage and hypervascularity in association with sinonasal masses may allow radiologists to narrow the differential diagnosis and begin planning further work-up and treatment. Localizing abnormal blood vessels in hypervascular masses may also help to avoid complications related to biopsy and/or surgery. The purpose of this article is to review the imaging and histopathologic features of hemorrhagic and hypervascular sinonasal masses, including sinonasal organized hematoma, lobular capillary hemangioma, cholesterol granuloma, reparative giant cell granuloma, juvenile nasopharyngeal angiofibroma, rhabdomyosarcoma, hemangiopericytoma, hemangioma, sinonasal mucosal melanoma, and metastases. In this article, we present CT and MR imaging algorithms for arriving at a diagnosis and provide a differential diagnosis for sinonasal lesions that mimick hemorrhagic and/or hypervascular masses.

Upon completion of this activity, participants will gain strategies to:
-Understand the differential algorithm for CT evaluation of hyperdense sinonasal masses in both pediatric and adult patients.
-Understand the differential algorithm for MR evaluation of T1 bright or enhancing sinonasal masses in pediatric and adult patients.
-Compare and contrast hemorrhage mimics on both CT and MRI such as mucoceles, chondroid lesions, or allergic fungal sinusitis.