Differentiation of Cocaine-Induced Midline Destructive Lesions from ANCA-Associated Vasculitis

INTRODUCTION: Cocaine-induced midline destructive lesions (CIMDL) are complications of regular nasal cocaine inhalation. CIMDL can mimic systemic diseases with positive anti-neutrophil cytoplasmic antibodies (ANCA), such as granulomatosis with polyangiitis (GPA). CASE REPORT: In this article, we describe the case of a young woman who presented with nasal perforation induced by cocaine, along with positive perinuclear ANCA test (proteinase 3 antigen), misdiagnosed as limited GPA. The patient was treated with immunosuppressive therapy, which partially improved her symptoms. Admittance of cocaine use aided in the diagnosis of CIMDL. This patient was advised to stop cocaine use. Three-month follow-up revealed no further complications. CONCLUSION: Considering the seropositivity of ANCA in both CIMDL and GPA, early diagnosis of CIMDL and its differentiation from GPA is crucial, and clinicians play an important role in this regard. Lack of distinct histologic characteristics of vasculitis or unresponsiveness to standard therapeutic regimens may favor the diagnosis of CIMDL syndrome. It is crucial to recognize that these conditions may have similar presentations, so that undesired and potentially toxic treatments can be prevented.