Tubercular fistula in ano.

Of 122 patients with fistulae in ano operated upon in a 5-year period, 19 (15.6 per cent) were found to have tubercular fistulae on histopathological examination. There was no characteristic clinical picture and concomitant pulmonary tuberculosis was present in only three patients. Histological examination of the excised fistula is mandatory for the diagnosis of anal tuberculosis. There were no cases of Crohn's disease of the anal region.