Algorithmic Approach to Fibroinflammatory Sinonasal Tract Lesions.

Fibroinflammatory lesions of the sinonasal tract are one of the most common head and neck lesions submitted to surgical pathology. When the fibroinflammatory pattern represents the lesion (i.e., not surface reactive ulceration), an algorithmic approach can be useful. Separated into reactive, infectious, and neoplastic, and then further divided based on common to rare, this logical progression through a series of differential considerations allows for many of these lesions to be correctly diagnosed. The reactive lesions include chronic rhinosinusitis and polyps, granulomatosis with polyangiitis, and eosinophilic angiocentric fibrosis. Infectious etiologies include acute invasive fungal rhinosinusitis, rhinoscleroma, and mycobacterial infections. The neoplastic category includes lobular capillary hemangioma, inflammatory myofibroblastic tumor, and NK/T-cell lymphoma, nasal type. Utilizing patterns of growth, dominant cell types, and additional histologic features, selected ancillary studies help to confirm the diagnosis, guiding further clinical management.