Utility of fine-needle aspiration cytology in the classification of leprosy

The role of fine-needle aspiration cytology (FNAC) in the diagnosis of beni gn skin lesions has been restricted primarily to the evaluation of bacterio logic and morphologic indices in leprosy. This study was undertaken to eval uate the efficacy of FNAC in the diagnosis and classification of lepromatou s lesions. Aspirates of 94 newly diagnosed cases of leprosy were studied, a nd tile bacterial load was determined by modified Ziehl-Neelsen (ZN) stain. A skin biopsy was taken from the same site fit the same sitting. Frozen an d paraffin sections stained with hematoxylin-eosin (H&E) and ZN stains were examined from tile biopsy specimen. In 61 of 94 cases (64.9%), the aspirat es were satisfactory. Both diagnosis and classification of leprosy were pos sible in 40 of these 61 cases; the rest of the aspirates showed nonspecific chronic inflammation, Tile 39 eases of leprosy where a biopsy was availabl e from the same site were classified on FNAC into tuberculoid (TT and BT), lepromatous (LL and BL), and midborderline (BB) subtypes. Taking the histol ogic diagnosis and Ridley-Jopling classification to be the gold standard, a strong concordance in tuberculoid leprosy cases (18 of 20 cases, 90%) and in lepromatous cases (15 of 16 cases, 93.7%) was observed. Midborderline ca ses of leprosy posed a problem, and a correct cytohistological correlation was observed in only one of the three cases. (C) 2001 Wiley-Liss, Inc.