Midline Destructive Lesions: Differentiating Granulomatosis With Polyangiitis From Cocaine-Induced Perforations.

Granulomatosis with polyangiitis (GPA) is a rare autoimmune vasculitis that may present with midline destructive lesions, often overlapping with conditions such as cocaine-induced midline destructive lesions (CIMDL). A 56-year-old man with a history of significant cocaine use (1 gram twice a week for three years, abstinent for five years) presented with chronic nasal congestion and epistaxis. He developed a large nasal septal perforation and later a palatal perforation. Laboratory workup revealed positive cytoplasmic antineutrophil cytoplasmic antibody (C-ANCA) with elevated proteinase 3 (PR3) levels, supporting the diagnosis of GPA. Despite an initial lack of granulomatous inflammation on biopsy, the patient's clinical presentation and positive response to immunosuppressive therapy confirmed GPA as the correct diagnosis. This case highlights the complexity of diagnosing GPA in a patient with a history of cocaine use. The positive C-ANCA result, systemic symptoms, and response to immunosuppressive treatment were key in establishing the diagnosis. It underscores the importance of considering GPA in the differential diagnosis of midline destructive lesions, even in the context of a history of cocaine use, and the need for timely and multidisciplinary management.