Papulonecrotic Tuberculid: A Rare Case Report

Tuberculids were originally felt to be related to an allergic response to tubercle bacilli in a patient with tuberculosis at a remote site. They are currently believed to be the result of hematogenous dissemination of organisms from an internal focus to the skin, where they incite a cutaneous inflammatory response. Papulonecrotic tuberculid (PNT) is a form of tuberculids that as the name implies presents clinically as necrotic papules. Herein, we report a case of 59-year-old man who presented with recurrent asymptomatic symmetrical necrotizing papules scattered on his trunk for 9 months. The patient has also crusted plaque on his right forearm. Two skin biopsies were made, one from papulonecrotic lesion on his trunk and the other one from the crusted plaque on his right forearm. The crusted plaque on the forearm showed granulomatous cellular infiltrates and caseation necrosis in the dermis, whereas the papulonecrotic lesions showed patchy perivascular mononuclear cellular infiltrates as well as granulomatous cellular infiltrates in the dermis. Tuberculin test was positive. A diagnosis of lupus vulgaris on the forearm and PNT on the trunk were made based on clinicopathological findings. The patient was seen by chest physician where there was no systemic involvement. Patient was treated successfully with anti-tuberculosis drugs for 9 months with complete resolution of all skin lesions.