A black cecum: diagnostic challenges and conservative management.

A 51-year-old man with type 1 diabetes mellitus and end-stage chronic kidney disease on hemodialysis presented with 12 hours of lower right quadrant abdominal pain and bloodless diarrhea. Examination showed tenderness without guarding. Blood tests showed leukocytosis (12200/microl) and elevated C-reactive protein (190 mg/L). Abdominal CT showed ascending colon thickening (~10 cm), mesenteric fat densification, and small locoregional ganglia, without signs of arterial/venous obstruction. Given the diagnostic doubt, colonoscopy was performed and revealed the cecum mucosa and ileocecal valve with a black color, with superficial ulceration of the proximal limit and sharp transition to normal mucosa. Biopsies of the cecum confirmed severe ischemic colitis with necrosis. Due to the absence of complications and high surgical risk, the patient was treated conservatively with fluids and antibiotics, resulting in a favorable outcome and hospital discharge.