Use of fine needle aspiration cytology in leprotic lesions: a report of 4 cases.

BACKGROUND: Although a few studies have shown fine needle aspiration cytology (FNAC) to be a sensitive diagnostic tool in the detection of nerve involvement, its role as an initial diagnostic procedure in pure neuritic leprosy (PNL) and in the detection of skeletal lesions with unusual findings has not been documented before. CASES: Three patients who presented with thickened nerves and a fourth with biopsy-proven lepromatous leprosy with lesions in hand bones underwent FNAC. Of the 3 patients with nerve thickening, 2 had a clinical suspicion or diagnosis of neuritic leprosy, whereas in the third patient a clinical differential diagnosis of a soft tissue tumor or parasitic cyst was considered. FNAC in all 3 cases revealed epithelioid cell granulomas, Langhans giant cells and caseous necrosis. Fites and Ziehl-Neelsen stains were negative for acid-fast bacilli. Cytologic diagnosis of pure neuritic leprosy was made in all 3 cases and confirmed by histopathologic examination. FNAC of skeletal lesions from the fourth patient confirmed involvement of bone with unusual cytologic findings of epithelioid cell granulomas and giant cells along with a significant proportion of foamy macrophages and strong Fites stain positivity. CONCLUSION: FNAC is a simple, useful, minimally traumatic and routinely applicable procedure in the diagnosis of pure neuritic leprosy and leprous osteitis.