A Kaposi sarcoma-like presentation in Borderline Tuberculoid leprosy: a case report and review

Abstract

Leprosy, or Hansen’s disease, is a chronic infectious disease caused by Mycobacterium leprae. It affects the skin, peripheral nerves, and eyes¹. Although curable with multidrug therapy (MDT), nearly 200,000 new cases are reported globally each year³. Early diagnosis and efforts to reduce social stigma are essential for disease control and prevention².

Leprosy and human immunodeficiency virus (HIV) infection frequently coexist in endemic regions, yet their immunologic interaction remains complex and paradoxical. Although HIV-induced immunosuppression could theoretically increase susceptibility to Mycobacterium leprae, the clinical spectrum of leprosy is not markedly altered in most co-infected patients^12,13.

We present the case of a male patient with a known history of HIV, who presented with erythematous and violaceous lesions suggestive of Kaposi sarcoma. The lesions, characterized by both plaques and nodules, were widely distributed across the face, trunk, back, and extremities. A slit-skin smear yielded negative results, while a biopsy from the left arm revealed elongated sausage-like tuberculoid granulomas in the superficial perivascular plexus and along the neurovascular bundle. The Fite stain failed to reveal the organisms. Further examination using fluorescent staining with auramine O showed a positive result in the left ear. In addition, molecular analysis via Nested PCR targeting the M. leprae-specific repetitive element (RLEP) confirmed a diagnosis of leprosy. The patient underwent multidrug therapy, after which the skin lesions showed improvement. Fluorescent staining and nested PCR testing may aid in diagnosing cases of paucibacillary leprosy, where slit-skin smear examination is often inconclusive. These methods may serve as supplementary diagnostic tools, particularly in cases presenting with atypical skin lesions.