RESUMEN
Abstract Rationale Perianal tuberculosis is extremely rare without previous or active pulmonary infection. Ulcerative skin lesion is a rare presentation of extrapulmonary tuberculosis in the oral, perianal, or genital mucosa and the adjacent skin. Case report A 71-year-old woman complained of pain during evacuation and fecal incontinence for two years. There was an ulcerated lesion in the perianal and intergluteal region and perianal fistulous tracts. A polymerase chain reaction test on blood and biopsies of perianal ulcers, perianal fistula, and the intergluteal area was positive for Mycobacterium tuberculosis. The pathological examination revealed a chronic epithelioid granulomatous inflammatory process with the presence of multinucleated giant cells. After the end of the tuberculosis drug regimen, there was marked improvement in the patient's clinical condition. Conclusion Even in the absence of an identifiable primary focus, tuberculosis should be considered in the differential diagnosis of ulcerative and fistulous lesions of the perianal area.