Primary hepatic neuroendocrine tumor: A case report and literature review

Abstract

Primary hepatic neuroendocrine tumors (PHNETs) are extremely rare and difficult to distinguish from other liver tumors, such as hepatocellular carcinoma (HCC) and cholangiocarcinoma, based on medical imaging findings. A 70-year-old man was referred for evaluation of liver mass incidentally discovered on abdominal computed tomography. The characteristic finding from dynamic liver magnetic resonance imaging led to a diagnosis of HCC. The patient underwent right hepatectomy. Histopathological and immunohistochemical examination revealed grade 2 neuroendocrine tumor. The postoperative 24-h urinary excretion of 5-hydroxy-indolacetic acid was within the normal range. Further imaging investigations were performed. No other lesions were found making probable the diagnosis of PHNET. This case shows that the diagnosis of PHNET is a medical challenge, requiring differentiation of PHNETs other hepatic masses and exclusion of occult primary neuroendocrine tumors. The diagnosis of PHNET can be ascertained after long term follow-up to exclude another primary origin.

Keywords: Hepatocelluar carcinoma; Liver; Neuroendocrine tumor; Primary hepatic neuroendocrine tumor.

Figure 1

Dynamic liver magnetic resonance image showing a 6.8-cm solid mass in segments 8 and 7. A: Image obtained in the arterial phase, showing a lobulated enhancing mass; B: Image obtained in the portal phase, showing the mass evolving into a low-density mass.

Figure 2

Pathological findings. A: Microscopic appearance of the tumoral lesion in the resected liver specimen. The architectural pattern is trabecular and glandular. Hematoxylin-eosin staining × 100; B: Diffuse, moderate immunoreactivity for chromogranin in the tumor cells. Immunohistochemical (IHC) staining, × 100; C: Negative immunoreactivity for Heppar-1 in tumor cells, and positive immunoreactivity occurs in normal hepatic cells. IHC staining, original magnification × 100; D: The Ki67 proliferation index is 10% in tumor cells. IHC staining, original magnification × 400.

Figure 3

Single-photon emission computed tomographic images obtained 24 h after the administration of indium-111 octreotide. Both the anterior and posterior whole body images show, no abnormal lesions with increased uptake. RT: Right; LT: Left.