Tuberculoid leprosy and tuberculosis skin: a comparative histopathological study.

Since it has been found hard to differentiate histopathologically tuberculoid leprosy from tuberculosis of the skin, a study of 20 biopsies from each of those conditions was undertaken to identify if possible some of their characteristic features. In tuberculoid leprosy along with tuberculoid granulomata there is always selective involvement and destruction of nerves, lack of fibrosis, absence of caseous necrosis and often epidermal atrophy. In cutaneous tuberculosis, on the other hand, in addition to tuberculous granuloma, there is often a proliferation reaction of the epidermis, areas of ulceration, absence of nerve destruction, marked increase in the reticulin, significant fibrosis and occasionally caseous necrosis.