A 42-year-old woman with a personal history of umbilical hernia surgery and hypertension. She presented with pain in the FII of 2 years' evolution, rectal tenesmus and flat stools. Physical examination revealed diffuse pain on deep palpation in the FII. Blood tests showed 16,000 leukocytes and 91% neutrophils. A barium enema and colonoscopy were performed, both of which revealed a stenosing image at the level of the sigma. Histological study of the biopsies was inconclusive. Resection of the stenosis area with end-to-end anastomosis was performed. The histological study confirmed the lesion of endometriosis of the colon with transmural involvement causing areas of fibrosis and haemorrhage.