Successful treatment of a case with pancreatic neuroendocrine carcinoma with focal hepatoid differentiation: a case report and literature review

A 33-year-old Chinese woman was admitted to our hospital because of an elevated serum alpha-fetoprotein (AFP) level (300 ng/mL) found in a regular medical checkup. Computed tomography imaging of the abdomen revealed a 1.6 x 2.2 cm low-attenuation mass in the head of the pancreas, with no enlarged lymph nodes and no metastatic liver nodules, and a pancreaticoduodenectomy was performed and the tumor was completely removed. The tumor was solid, unencapsulated and poorly demarcated, measuring 2 x 1.4 x 1.8 cm, and the cut surface was grey-yellowish. Histologically, most of the areas of the tumor were composed of small monotonous and round shaped neuroendocrine cells, and approximately 20% of the areas were cells with indistinct cytoplasmic borders, large oval nuclei, prominent nucleoli and abundant eosinophilic cytoplasm, resembling the appearance of HCC. Immunohistochemical stains revealed that the neuroendocrine areas were diffusely positive for chromogranin, and the hepatoid areas showed diffuse and strong positive reaction to AFP. After surgery the AFP level reduced to normal. She received six cycles of postoperative chemotherapy and three years after the surgery was found to have an elevated serum AFP level again which gave rise to the suspicion of tumor recurrence, and a positron emission tomography-computed tomography confirmed the speculation by showing a hypermetabolic lymph node behind the body of the pancreas. She then underwent radiotherapy and the AFP level reduced to normal. Up till now she has survived 46 months since the initial diagnosis. This case and previous cases suggest that the serum AFP could be a useful marker for early detection of the disease, but careful differential diagnosis should be performed, and AFP could also be a marker for evaluation of therapeutic response and recurrence of the AFP-producing hepatoid carcinomas of pancreas.