Introduction and importance: Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies in Indonesia and is well-known as a silent killer disease due to its mortality rate among males. Furthermore, a pedunculated HCC (P-HCC) is a rare subtype challenging to diagnose when presented as an extrahepatic mass. Case presentation: A 61-year-old man was admitted to our hospital due to abdominal pain with a palpable mass in the left upper abdomen after being referred from secondary health care. The laboratory results revealed values within normal ranges, except for reactive anti-HCV and anemia, with no evidence of liver abnormalities. CT scan detected a solid mass with a necrotic center and calcified component in the upper left hemiabdomen originating from the submucosa of the greater curvature of the stomach, which were suggestive of gastrointestinal stromal tumor (GIST). It was approximately 12.9 × 10.9 × 18.6 cm sized, multilobulated, well-defined, and infiltrating the splenic vein. Clinical discussion: We did a laparotomy and resections consist of distal gastrectomy, liver metastasectomy (segment 2–3), distal pancreatectomy, and splenectomy. Our operative findings were still suggestive of neoplasm of the stomach, most likely a GIST. However, our histological examination revealed a moderate-poorly differentiated liver cell carcinoma, confirmed with immunohistochemical analysis. He was discharged on the seventh day after the operation without any complications. Conclusion: This case illustrates challenges in diagnosing and treating a rare pedunculated hepatocellular carcinoma. © 2023