Transformation of a case of tuberculoid leprosy in reaction to the lepromatous form.

In an inquiry about the evolution of tuberculoid leprosy, I wrote in 1936 (7), that I had not seen a typical case of tuberculoid leprosy-characterized clinically by its well-defined lesions, bacteriologically by the absence of bacilli, histologically by tuberculoid structure, and immunologically by a positive reaction to lepromin-undergo transformation to the typical lepromatous condition with its characteristic features-diffuse, poorly delimited lesions, abundant bacilli, lepromatous histology, and negativity to the Mitsuda test. I asked for the opinion of other specialists on the matter, and added that if the majority of leprologists should assert that they had not observed this transformation, that fact would argue in favor of recognition of the tuberculoid form as a distinct type, separate from the neural and lepromatous forms. Up to the present time I know of no report of the transformation of a typical tuberculoid case, one which could be called complete in that it had been shown to possess all of the characteristics mentioned, into a frank lepromatous case, nor have I observed that occurrence myself until now. With the acquisitition of knowledge of the condition known as tuberculoid leprosy reaction, first described by Wade (12) and then by Schujman (6), Fernandez (3), Souza Campos(9) and others, cases in which the process of infection is accentuated, with abundant and marked lesions and with transitorially positive bacteriology, it was thought-and with some reason-that perhaps such cases might under some circumstances evolve to the lepromatous form.