Cryptogenic Pyogenic Liver Abscess as a Sentinel of Occult Colorectal Cancer: Successful Conservative Management of a Rare Presentation.

Pyogenic liver abscess (PLA) is an uncommon but serious infection, usually linked to biliary or intra-abdominal sources. When no clear cause is identified, the possibility of an underlying gastrointestinal malignancy, especially colorectal cancer (CRC), should always be considered. In some cases, a liver abscess may be the very first sign of an otherwise silent cancer. We report a 68-year-old woman with a history of breast cancer, chronic obstructive pulmonary disease, and non-alcoholic fatty liver disease, who presented with sepsis and confusion. Imaging revealed multiple large, multiseptated liver abscesses. Despite their size, she was treated successfully with antibiotics alone, without drainage. A few weeks later, she was readmitted with abdominal pain, iron deficiency anemia, and Clostridium difficile colitis. Colonoscopy revealed an ascending colonic adenocarcinoma. She underwent right hemicolectomy, and pathology confirmed stage II colonic carcinoma. Her earlier liver abscesses were later recognized as the first sign of her underlying cancer. This case highlights the importance of evaluating cryptogenic liver abscesses for occult CRC. It also shows that, in selected patients, even large, complex abscesses can respond well to antibiotics alone. Early multidisciplinary involvement and clinical suspicion are key.