Giant hepatoid adenocarcinoma of the transverse colon in an 84-year-old woman: A case report and review of the literature

Rationale: Hepatoid adenocarcinoma (HAC) is a rare extrahepatic tumor. The most common origin of HAC was the stomach (63%). HACs originating from the colon or rectum are rare. Patient concerns: An 84-year-old Chinese woman was presenting with a large abdominal mass. Imaging revealed an irregularly thickened transverse colon wall with its greatest dimension over 15 cm. Colonoscopy identified a space-occupying lesion in the transverse colon. Diagnoses: Histopathology confirmed poorly differentiated adenocarcinoma with partial hepatoid differentiation. Interventions: The patient underwent an extended right hemicolectomy and partial small intestinal resection. Immunohistochemistry revealed mismatch repair deficiency characterized by MLH-1 and PMS-2 loss. Outcomes: The patient recovered and was discharged. At 30 months of follow-up, no recurrence or metastasis was observed. Lessons: HACs are less likely to occur in the colorectum. We recommend that surgeons intervene aggressively if the patient’s condition permits.