Hepatoid adenocarcinoma of the stomach: an unusual case of elevated alpha-fetoprotein with prior treatment for hepatocellular carcinoma

Abstract

Hepatoid adenocarcinoma (HAC) is a rare type of extrahepatic carcinoma whose morphology is similar to that of hepatocellular carcinoma (HCC). Metachronous HCC and HAC in the same patient is extremely rare. The case of a 68-year-old man with chronic hepatitis B infection who had both HCC and HAC of the stomach is reported herein. Nine years previously this patient had been diagnosed with HCC and received a right lobectomy. HCC that recurred at the caudate lobe at 6 months after the operation was successfully treated with transarterial chemoembolization. The patient was followed up regularly thereafter without evidence of tumor recurrence for 9 years. In July 2010 his serum alpha-fetoprotein (AFP) level elevated from 6.5 ng/mL to 625.4 ng/mL, and he developed a probable single metastatic lymph node around the hepatic artery without intrahepatic lesions. Subsequent evaluation with upper endoscopy revealed a 4-cm ulcerative lesion on the antrum of the stomach. Subtotal gastrectomy was performed with lymph-node dissection. Histologic examination revealed a special type of extrahepatic AFP-producing adenocarcinoma-HAC with lymph-node metastasis-which indicates that HAC can be a cause of elevated AFP even in patients with HCC. HAC should be considered if a patient with stable HCC exhibits unusual elevation of AFP.

Keywords: Hepatocellular carcinoma; Hepatoid adenocarcinoma; Metachronous; Stomach.

Figure 1

(A, B) Liver computed tomography (CT) scan showed a 3-cm arterial enhancing lesion with delayed washout at segment 6/7 of the liver (A, arterial phase; B, portal phase). (C, D) Tumor in the liver showed Edmondson grade II HCC (C: H&E, ×100, D: H&E, ×400).

Figure 2

(A) Upper endoscopy revealed a 4-cm ulcer on the lesser curvature side of the antrum of the stomach. It is morphologically suspicious of early gastric cancer type III. (B-E) Tumor in the stomach showed an HAC. It was immunohistochemically positive for AFP and polyclonal carcinoembryonic antigen (CEA) (B: H&E, ×100; C: H&E, ×400; D: AFP, ×100; E: polyclonal CEA, ×100).

Figure 3

(A) CT scan showed multiple hepatic nodules. (B-E) Microscopic images including immunohistochemical results of a liver biopsy specimen showed tumor cells that are positive for AFP and cytokeratin 19 (CK19), and focally positive for CEA (B: H&E, ×100; C: AFP, ×100; D: CEA, ×100; E: CK19, ×100).