An underweight, 8-year-old boy presented with painless ulcer on the left retro-auricular region with an undermined edge, pale granulation tissue on the floor and surrounding bluish hue. Two painless ulcers were also present on dorsum of right foot (Fig. 1). Initially the lesions were firm, erythematous, non-tender nodules which softened to become abscess and broke down to form ulcers over two months. Systemic examination revealed no abnormalities. Investigations revealed anemia (hemoglobin 7 g/dL), high ESR (60 mm), and a positive mantoux test (20mm).VDRL and ELISA for HIV were not contributory. The X-ray chest and of local part were normal. Aspiration cytology from the ulcer was negative for acid fast bacilli, fungal elements and anerobic organisms. Histopathology of the lesion showed granuloma with widespread caseation necrosis. Anti- tubercular therapy with four drugs regimen was started and he had remarkable improvement with healing of ulcers and weight-gain.

Fig.1 Multiple deep seated ulcers with undermined edge on the dorsum of the right foot (A), and left retro auricular area (B); Highly reactive mantoux test(C).

Tubercular gumma is a rare (1-2%) form of cutaneous tuberculosis caused by hematogenous dissemination. Presence of tubercles with widespread caseation necrosis is diagnostic on histopathology. Clinically, it is difficult to differentiate from syphilitic gumma, pyoderma gangrenosum, atypical mycobacterial lession and subcutaneous fungal infections. It should be confirmed by histopathology and culture. Pyoderma gangrenosum has a rapidly progressive course with a invariably painful ulcer. Pathergy phenomena is positive and histopathology shows neutrophilic inflammation and necrosis. There is a tendency for central necrosis and ulceration with peripheral healing and tissue paper scrapping in syphilitic gumma. Subcutaneous mycoses is diagnosed by direct microscopic examination with KOH, histopathology with special stains (PAS, Gomori, Grocott) and fungal culture.