Early leprosy with perineural proliferation

A 62-year-old woman, who lived in an area of the United States nonendemic for leprosy, was seen for an enlarging anesthetic lesion that involved the entire left breast. Microscopic examination of skin biopsy specimens taken from the edge of the lesion disclosed chronic perineural inflammation and neural proliferation, with an acid-fast bacillus demonstrable in one nerve. Granulomas, giant cells, epithelioid cells, nerve abscesses, or other characteristics of tuberculoid leprosy were not seen. This woman had a skin lesion of leprosy in an atypical site. It appeared to be indeterminate on pathologic examination and was accompanied by an unusual degree of neural proliferation.