Dear Editor: Diverticulitis associated with free perforation and fecal or purulent peritonitis is a surgical emergency, with an associated mortality of up to 35%. Diverticular perforation into an adjacent organ can be followed by fistula formation. We report the case of a patient referred to our hospital with sigmoid diverticulitis and fecal peritonitis, which subsequently developed a complex fistula, as well as left hip septic arthritis. A 41-year-old male patient was transferred to our hospital after an acute episode of purulent sigmoid diverticulitis 2 months before; a transverse colostomy and drainage were performed. The patient was transferred due to a painful left lower extremity deformity and recurrent urinary tract infections despite antibiotic during the last 6 weeks. He showed physical signs of malnutrition, a left lower extremity flexion and adduction deformity, very limited hip motion due to pain and thigh muscular contracture, a fistulous sinus in the left lower quadrant with fecal discharge, and turbid urine through a urinary catheter. The patient denied any previous history of hip or extremity affection. Urine cultures were positive for Escherichia coli. On radiographs, a left adduction deformity and femoral head destruction suggested septic hip arthritis. The Department of Orthopedic Surgery recommended no urgent drainage since no septic state was found. A cystography showed contrast material passage to the sigmoid and left hip cavity. After a 10-day period of nutrition and systemic antibiotics, the patient was scheduled for a laparotomy. Surgical findings: a paracolic abscess and an inflammatory process affecting the sigmoid, dense adhesions to the bladder fundus, an ileum segment, iliac bone and lateral pelvis abdominal wall; fistulous communications medially from the sigmoid to the bladder and ileum 40 cm from the ileocecal valve, and laterally to the iliac bone, where the sigmoid was densely adhered to and below the inguinal ligament. Approximately 0.5 L of purulent material was drained through a communication with the hip joint cavity. An anastomosis was not considered due to the inflammatory and infectious process. Resection of the sigmoid and left colon distal to the transverse colostomy plus a Hartmann's procedure was performed. The segment of affected ileum and fistulous orifice in the bladder were resected. Ileum anastomosis and bladder repairs were practiced. Pathologic exam revealed perforated sigmoid diverticulitis, colon diverticulosis, fibrous reaction surrounding the bladder wall and ileum fistulous orifices, and absence of malignancy. After an uneventful recovery, the patient is under physical therapy. Hip replacement and bowel continuity reestablishment will be practiced. Hinchey et al. described a grading system for colonic diverticulitis. Stage I diverticulitis involves a pericolic abscess; Stage II, a distant abscess, retroperitoneal or pelvic; Stage III, purulent peritonitis; and Stage IV, fecal peritonitis. Stages III and IV are surgical emergencies, with associated mortalities of up to 35%, depending on the degree of fecal contamination, sepsis and surgical intervenNo disclaimers. There was no financial support. The paper was not presented in any meeting. It includes a list of contribution of each author/coauthor. The three authors participated in conception and design, acquisition of data, critical revision of the article, and final approval. C. M. Nuno-Guzman : J. M. Hernandez-Carlin : F. I. Almaguer Antiguo Hospital Civil de Guadalajara “Fray Antonio Alcalde”, Calle Hospital 278, Guadalajara, Jalisco, Mexico 44280