Fine needle aspiration cytology of leprous neuritis

OBJECTIVE: To document the cytomorphologic features of leprous neuritis and their correlation with bacterial density. STUDY DESIGN: A partly retrospective, partly prospective study of the fine needle aspiration cytology of enlarged nerves in leprosy. Cytomorphologic features of nerve aspirates from 28 patients were studied. May-Grünwald-Geimsa and Ziehl-Neelsen staining methods were employed. RESULTS: Five cytomorphologic patterns were observed in smears of nerve aspirates in 19 group I patients with concurrent skin and nerve lesions: (1) inflammation composed of epithelioid cell granulomas (5), bacillary index (BI) = 0; (2) epithelioid cell granulomas with necrosis (5), BI = 0-1+; (3) acellular necrosis (5), BI = 0-4+; (4) macrophage granuloma (3), BI = 5-6+; and (5) granulation tissue (1), BI = 1+. In 9 group II patients with pure neuritic leprosy, 3 patterns were seen: (1) epithelioid cell granulomas (5), BI 0-6+; (2) epithelioid granulomas with necrosis (1), BI = 0; and (3) acellular necrosis (3), BI = 0-6+. CONCLUSION: The entire spectrum of leprosy is seen in nerve aspirates. Necrosis is often a prominent feature. Recognition of the range of cytomorphologic patterns and their correlation with BI contribute to accurate calibration of the disease in nerves, resulting in appropriate choice of treatment.