Abstract

Lepromatous leprosy (LL), also known as multibacillary leprosy, is a rare chronic infection characterized by widespread, erythematous, and ill-defined macules, papules, plaques, and nodules most often involving the face and extremities as well as development of stocking-glove sensory changes. Characteristic histopathologic findings include perivascular lymphohistiocytic infiltrates, sheets of histiocytes sparing the papillary dermis, as well as amphophilic collections of acid-fast bacilli within histiocytes termed globi that stain strongly with Fite stain. On evaluation of hematoxylin-eosin (H&E) specimen, acid-fast bacilli are most often identified using a Fite stain which has a higher sensitivity than Ziehl-Neelson and Acid-Fast Bacilli (AFB) stains. We present a peculiar case of multibacillary leprosy identified by positive AFB in the absence of globi in a patient with an evolving cutaneous eruption and sensory impairment of the hands and feet. Initially, this patient presented with scaly erythematous plaques which revealed a non-specific lymphohistiocytic infiltrate on biopsy and favored to be a drug-induced process. The eruption persisted despite discontinuation of multiple medications and over time the existing plaques became less scaly and there was development of new pink to orange nodules. Repeat biopsy of one of the new nodules revealed a superficial and deep histiocytic infiltrate with a grenz zone and positive AFB. Confirmatory polymerase chain reaction (PCR) testing was positive for mycobacterium leprae. This case highlights the importance of repeat biopsy in the setting of evolving cutaneous morphology and presents a unique case of multibacillary leprosy identified by AFB staining despite the absence of globi on pathology.