Alpha-fetoprotein-producing clear cell carcinoma of the gallbladder with neuroendocrine differentiation.

An uncommon case of alpha-fetoprotein (AFP) producing clear cell carcinoma of the gallbladder with neuroendocrine differentiation in a 78-year-old Japanese woman, who complained of epigastralgia, is reported. Macroscopically, the nodular infiltrative type of tumor, measuring approximately 4.5 × 3.5 cm in size, was located in the fundus of the gallbladder. Histologically, the tumor was composed of clear cell carcinoma with AFP production, non-clear cell adenocarcinoma with neuroendocrine differentiation, and poorly or undifferentiated carcinoma with extensive ulceration. Carcinoma in situ was found in the surrounding gallbladder epithelium. Her postoperative laboratory tests showed a decrease in AFP levels to normal. The clinical and pathologic significance of AFP production or neuroendocrine differentiation in the gallbladder carcinomas have thus far remained completely obscure. However, we should recognize the entity of this tumor because the accurate diagnosis of primary clear cell carcinoma of the gallbladder may have important therapeutic implications.