Perforated hepatic flexure adenocarcinoma mimicking pyogenic hepatic abscess: A CT diagnostic pitfall

Perforated colorectal carcinoma may present with inflammatory and septic features that obscure the underlying malignancy. Tumors arising at the hepatic flexure are particularly challenging because of their close anatomical relationship with the liver, allowing perforation-related inflammation and necrotic hepatic metastases to mimic pyogenic hepatic abscesses on imaging. A 58-year-old man with hypertension and human immunodeficiency virus (HIV) infection receiving antiretroviral therapy presented with acute abdominal pain, fever, chills, and systemic inflammatory symptoms. Ultrasound demonstrated hepatic lesions and irregular hepatic flexure wall thickening suspicious for malignancy, while contrast-enhanced CT showed multiple abscess-like hepatic lesions with features of both metastatic disease and perforation-related inflammation. Emergency laparotomy revealed a perforated hepatic flexure tumor densely adherent to the liver, with fibrinopurulent exudate, an inflammatory tract between the hepatic flexure and adjacent liver, multiple hepatic nodules, and peritoneal tumor seeding; histopathology confirmed moderately differentiated adenocarcinoma with hepatic and nodal metastases and central necrosis in the hepatic lesions (pT4N2M1). This case highlights the diagnostic overlap between pyogenic hepatic abscesses and necrotic hepatic metastases associated with perforated colorectal carcinoma. When abscess-like hepatic lesions coexist with irregular colonic wall thickening, regional lymphadenopathy, or loss of normal tissue planes, colorectal malignancy should remain an important consideration despite accompanying inflammatory features.