Isolated left-lobe metastatic hepatic abscess due to portal pyemia from microperforated ascending colon carcinoma: a rare case report.

INTRODUCTION AND IMPORTANCE: Liver abscess-like lesions are commonly managed as primary hepatobiliary infections; however, colorectal cancer can be an occult source, particularly when portal pyemia follows a microperforated tumor. Diagnostic complexity increases when right-sided colon cancer presents with an apparently isolated left-lobe hepatic collection mimicking foregut disease, especially in settings where anaerobic culture and immunohistochemistry are limited.

CASE PRESENTATION: A middle-aged woman in her fifth decade with an 8-month history of intermittent right iliac fossa pain and recurrent loose stools represented with sepsis after deferring surgery for a colonoscopically detected ascending-colon mass. She had previously been advised surgical resection but left against medical advice and pursued traditional treatments, resulting in an 8-month diagnostic-to-intervention delay. Contrast-enhanced computed tomography showed a large ascending-colon tumor with suspected microperforation, pericolic lymphadenopathy, ileocolic vein thrombosis, an appendiceal mucocele, and a left-lobe subcapsular hepatic collection with peripheral enhancement and internal gas. A presumed gastric mass was later explained intraoperatively by extrinsic compression from the ruptured collection. Laparotomy with drainage and right hemicolectomy was performed. Histopathology confirmed moderately differentiated ascending-colon adenocarcinoma, pT3N1a, R0, with 1 of 18 nodes positive, and a low-grade appendiceal mucinous neoplasm. A hepatic core biopsy demonstrated metastatic well-differentiated adenocarcinoma within an abscessed, necrotic inflammatory background, confirming a metastatic hepatic abscess.

CLINICAL DISCUSSION: Pyogenic liver abscess (PLA) may rarely represent the first clinically overt manifestation of occult colorectal carcinoma, though in this case, right iliac fossa pain was the earliest symptom, with the hepatic abscess emerging as the complication that precipitated the final presentation. Imaging and limited biopsy sampling created uncertainty as to whether the lesion was an abscess or a necrotic metastasis. Cryptogenic PLA warrants evaluation for underlying colorectal malignancy. Early antibiotics and surgical source control are essential. The postoperative course was complicated by a superficial surgical site infection (Clavien-Dindo Grade I) due to methicillin-resistant Staphylococcus aureus, managed with wound care and targeted antimicrobials.

CONCLUSION: Right-sided colon cancer complicated by microperforation and portal pyemia can culminate in a ruptured left-lobe metastatic hepatic abscess that mimics foregut pathology, creating a multilayered diagnostic challenge. This case underscores the importance of early cross-sectional imaging, prompt oncologic source control, and integrated pathology-oncology collaboration. Clinicians should maintain a low threshold for investigating colorectal malignancy in patients presenting with cryptogenic PLA, as early recognition and timely surgical intervention are critical to optimizing oncologic and infectious outcomes.