Histology of indeterminate leprosy.

Skin biopsies from 20 patients with indeterminate leprosy were studied histopathologically. The most common clinical manifestation of the disease was a hypopigmented macule. In most cases, 5% to 10% of the dermis was occupied by the infiltrate. Sweat glands were involved in two thirds of the cases, and approximately half the biopsies showed involvement of arrector pili muscle and pilosebaceous glands. Ninety-five percent of the cases had involvement of the dermal nerves, with perineural infiltration being the most common finding. Twenty-five percent of the cases showed lesions of the epithelium.