Primary hepatic carcinoid tumors are extremely rare although the liver is a frequent site of metastases from intestinal carcinoids. Recently we investigated a case of primary hepatic atypical carcinoid in a 47-year-old man who had infested with Clonorchis sinensis for 20 years. The resected right lobe of the liver was almost completely occupied by a huge tumor, measuring 20 x 19 x 12 cm. The cut surfaces of the mass were solid, soft and pale yellow, accompanied by several small satellite nodules, measuring up to 1.5 cm in diameter. Microscopically, the tumor consisted of polygonal to columnar cells with eosinophilic granular cytoplasm forming Lym-numerous small acini and large trabeculae. Their nuclei were round to polygonal with coarse stone chromatin, had obscure to small nucleoli and frequent mitoses. There were multiple necrotic foci of varing sizes. The surrounding dilated bile ducts contained several degenerating worms on in of Clonorchis sinensis. The tumor cells were argyrophil-positive but argentaffin-negative. Immunohistochemically, the tumor cells were positive for cytokeratin, chromogranin and somatostatin but were negative for CEA, AFP, insulin, glucagon, ACTH, growth hormone and volve-prolactin. Ultrastructually, the tumor cells contained variable-sized numerous electron dense of neurosecretory granules.