Nodular granulomatous phlebitis of the skin: a fourth type of tuberculid.

We present five cases of granulomatous phlebitis of the skin and compare them with a case of miliary tuberculosis with granulomatous phlebitis. All five patients were hypersensitive to purified protein derivative, but without active tuberculosis. Although anti-tuberculous drugs were effective, no tubercle bacilli were isolated from the skin. Clinically, subcutaneous nodules were felt along the course of the leg vein. Histologically, epithelioid cell granulomas with Langhans' giant cells were observed within the walls of the cutaneous veins. In a later stage, granulomatous panniculitis was often associated. Using the polymerase chain reaction method. Mycobacterium tuberculosis DNA was detected in four of the five cases of granulomatous phlebitis of the skin. Granulomatous phlebitis of the skin seems to represent a relatively early phase of delayed-type hypersensitivity reactions to Mycobacterium tuberculosis and may represent a distinct entity different from other types of tuberculid-a new tuberculid. Nevertheless, before making the diagnosis, the possibility of true tuberculosis must always be excluded. Nodular granulomatous phlebitis of the skin would be an appropriate name for the newly described condition.