Histoid leprosy with giant lesions of fingers and toes

This work was conducted at the Facultad de Medicina, Universidad de La Sabana, and at the Facultad de Medicina, Universidad Surcolombiana. Histoid leprosy, a clinical and histological variant of multibacillary leprosy, may offer a challenging diagnosis even for experts. An 83-year-old woman presented with papular, nodular and tumor-like lesions of 3 years of evolution, affecting fingers, toes, hands, thighs and knees, and wide superficial ulcers in her lower calves. Cutaneous lymphoma was suspected. A biopsy of a nodule of the knee showed a diffuse dermal infiltrate with microvacuolated histiocytes, moderate numbers of lymphocytes and plasma cells. Cutaneous lymphoma was suggested. Immunohistochemistry (IHC) showed prominent CD68-positive macrophages, as well as CD3, CD8 and CD20 positive cells. Additional sections suggested cutaneous leishmaniasis. New biopsies were sent with the clinical diagnoses of cutaneous lymphoma, Kaposi´s sarcoma or lepromatous leprosy, as the patient had madarosis. These biopsies showed atrophic epidermis, a thin Grenz zone and diffuse inflammation with fusiform cells and pale vacuolated macrophages. ZiehlNeelsen stain showed abundant solid phagocytized bacilli with no globii formation. Abundant bacilli were demonstrated in the first biopsy. Histoid leprosy was diagnosed. The patient received the WHO multidrug therapy with excellent results. We concluded that Ziehl Neelsen staining should be used in the presence of a diffuse dermal infiltrate with fusiform and vacuolated histiocytes, which suggests a tumor, and an IHC particularly rich in CD68-positive macrophages; this will reveal abundant bacilli if the lesion is leprosy. A good clinical pathological correlation is essential to establish a proper diagnosis and management of the patient.