Histoid leprosy – unusual presentation

Abstract

A 39-year-old man presented with a chronic nonhealing toe ulcer and multiple skin-colored papules on the back, arms, and knees. From an initial small erosion, the toe lesion ulcerated over a 1.5-year period, while the papules progressed over a 6-month period, first appearing on the back and then spreading to the arms and knees. The past medical and family history were non-contributory. Pertinent findings included the aforementioned well-defined, asymmetric, shiny papules (Fig. 1). There were multiple, discrete, erythematous, pedunculated, tumor-like masses of various sizes over the right thigh (Fig. 2) and a well-defined 4 cm x 3 cm ulcer on the second toe of the left foot, the floor of which was covered by necrotic slough. There was distal loss of sensation to temperature, touch, and pain. The greater auricular, ulnar, radial cutaneous and common peroneal nerves were thickened bilaterally, but non-tender. A clinical diagnosis of histoid leprosy was made. The differential diagnosis for the tumor-like thigh masses included dermatofibroma, neurofibroma, and Kaposi's sarcoma. The hemogram, liver/renal function tests, chest X-ray, and abdominal ultrasound were normal. Human immunodeficiency virus enzyme-linked immunosorbent assay (HIV ELISA) was negative. The ear lobe smear (ELS) for acid-fast bacilli showed a bacterial index (BI) of 6+[> 1000 organisms/oil immersion field (oif)] and a morphological index (MI) of 50%. The skin-colored papules on the back and the pedunculated masses showed a BI of 5+ (100-1,000 organisms/oif) and an MI of 50%. The normal skin showed a BI of 4+ (10-100 organisms/oif) and an MI of 5%. Biopsy of the papules and pedunculated tumors showed a well-circumscribed area of the dermis packed with many acid-fast organisms and foamy macrophages, consistent with histoid leprosy (Fig. 3). Fite-Faraco stain demonstrated cells packed with lepra bacilli. A final diagnosis of lepromatous leprosy, histoid variant, was made. Dapsone, clofazimine, rifampicin, and, later, ofloxacin were started.