HCC Metastasis to the Sigmoid Colon and Rectum

CASE REPORT Few cases of sigmoid colon and pelvic hepatocellular carcinoma (HCC) metastases have been reported.1–4 We report the case of a 70-year-old man with HCC who was successfully treated with multiple locoregional therapies. Nearly 6 years postdiagnosis, his alpha-fetoprotein (AFP) up trended to 18 ng/mL and surveillance MRI extended to the pelvis revealed a 3.1 × 4.0 cm T2 intermediate enhancing lesion involving the high rectum and sigmoid colon (Figure 1). Rectal endoscopic ultrasound revealed a round, intramural, hypoechoic lesion in the sigmoid colon (Figure 2). Biopsy showed a submucosal mass which was positive by immunohistochemistry for cytokeratin (CAM5.2), hepatocyte markers (HepPar1, arginase, and glypican), and patchy expression of CDX2, while negative for AFP, CK20, and CK7. The patchy positivity for CDX2 is a known pitfall for hepatocellular carcinomas. Hepatoid colorectal carcinomas rarely express all hepatocyte markers and are positive for AFP5 therefore this was felt to be less likely (Figure 3). Four months after stereotactic body radiation treatment, rectal lesion measured 3.3 × 1.7 cm (Figure 4). We demonstrate the importance of regular surveillance in recognizing atypical metastasis of HCC, especially when AFP levels are increasing. Our patient was likely at increased risk of colonic metastasis due to his longstanding history of poorly differentiated HCC.Figure 1.: MRI extended to the pelvis showing exophytic T2 intermediate enhancing lesion involving high rectum and sigmoid colon (3.1 × 4.0 cm).Figure 2.: Endoscopic imaging showing a submucosal nonobstructing mass within the sigmoid colon.Figure 3.: Histologic and immunohistochemistry expression of tumor: (A) Hematoxylin and eosin (H&E) of tumor with eosinophilic/hepatoid features, (B) glypican 3 diffuse positivity in tumor, (C) CDX2 patchy positivity in tumor, (D) Arginase diffuse positivity in tumor.Figure 4.: MRI pelvis showing an interval decrease in the size of the initial sigmoid colon lesion (3.3 × 1.7 cm).DISCLOSURES Author contributions: K. Kolluri wrote the manuscript. JJ Pan and L. Meurer saw the patient. K. Byrnes interpreted pathology. JJ Pan oversaw preparation of the manuscript and obtained verbal consent from the patient. L. Meurer is the article guarantor. Financial disclosure: None to report. Informed consent was obtained for this case report.