S5033 Cryptogenic Liver Abscess in a Colon Cancer Patient Presenting with Persistent Fever: A Diagnostic Challenge

Introduction: Pyogenic liver abscess is an uncommon but life-threatening condition that can present with fever, abdominal pain, and systemic inflammation. In patients with a history of gastrointestinal malignancy, hepatic lesions often raise suspicion for metastasis. Differentiating between malignant and infectious etiologies is critical for management. We present a diagnostically challenging case of liver abscess in a patient with prior colon cancer and recurrent fevers. Case Description/Methods: A 47-year-old woman with a history of stage III colon adenocarcinoma status post hemicolectomy (completed chemotherapy in 2022), hypertension, diabetes, iron deficiency anemia, and possible autoimmune disease presented with fever and myalgias. She had multiple prior admissions over the preceding 3 months for fever of unknown origin (FUO), with extensive negative infectious and oncologic evaluations. Work-up included a gallium scan (no abnormal uptake), magnetic resonance imaging (MRI) abdomen (2.9 cm hepatic lesion), and ultrasound-guided aspiration of a right hepatic dome lesion yielding bloody fluid negative for malignancy and culture. Blood cultures and transesophageal echocardiogram (TEE) were also unremarkable. She re-presented with fever to 104°F, chills, and worsening fatigue. Labs revealed leukocytosis (15K), thrombocytosis, elevated inflammatory markers and transaminitis. Computed tomography (CT) abdomen showed interval increase in the hepatic lesion to 6.6 cm with adjacent peripancreatic stranding, raising suspicion for liver abscess or malignancy. Despite multiple antibiotics and aspirations in prior admissions, the lesion persisted. Given her current SIRS criteria and the CT findings, she was admitted and started empirically on broad-spectrum antibiotics for presumed liver abscess. She remained hemodynamically stable without abdominal tenderness. Discussion: Liver abscess in patients with a history of gastrointestinal malignancy can be easily mistaken for metastatic disease. This case illustrates the importance of maintaining a broad differential in patients with persistent fever and hepatic lesions. Sterile or culture-negative abscesses may occur in immunocompromised or partially treated patients. Repeated imaging, aspiration, and a multidisciplinary approach including infectious disease, hepatology, and interventional radiology are crucial for diagnosis and treatment.