S11C8P3-3: This is a stable lesion with features of arrested disease. Vacuolated histiocytes are isolated by membranous deposits. The load of intra-cellular organisms generally is light in a lesion showing such patterns. There are few lymphocytes in the infiltrates.

S11C8P3-4: This lesion is composed of fibroblastic spindle cells that are arranged in the pattern of interlacing fascicles. At points of intersection the fascicles produce star-burst patterns (a so-called, fibro-histiocytic quality). In the region outlined by blue arrows, the cells are vacuolated histiocytes; they are rich in organisms. A proliferative lesion of this type is peculiar to lepromatous lesions which have been stablized by sulfone therapy. The appearance of clusters of organism-rich histiocytes, in this setting, is an expression of the emergence of resistance to sulfones. This is “histoid” leprosy , an unusual variant of lepromatous leprosy.

S11C8P3-5: In this field of a lesion of borderline leprosy, the patterns are epithelioid, but the epithelioid histiocytes are rather loosely spaced; lymphocytes are interspersed among the histiocytes. This is borderline leprosy with tuberculoid qualities.