Hepatobiliary cystadenocarcinoma with cystadenoma elements of the gall bladder in an old man

Hepatobiliary cystadenoma and cystadenocarcinoma of the gall bladder have rarely been reported. An 88‐year‐old Japanese man was admitted to our clinic because of hypochondralgia and jaundice. Imaging techniques revealed hemobilia and a multilocular cystic tumor in the fundus of the gall bladder, and cholecystectomy was performed. Grossly, the tumor (3.5 × 3 × 3 cm) was multicystic, containing seromucous fluid. The tumor was located in the fibromuscular layer and subserosa of the gall bladder fundus, and protruded into the serosal surface, not into gall bladder lumen. The mucosa appeared free of tumor involvement, and no gall stones were recognized. Microscopically, the tumor was located in the fibromuscular layer, subserosa and tiny focus of the mucosal surface. The tumor consisted of mucin‐rich benign columnar cells, dysplastic mucous cells, malignant papillotubular cells and invasive carcinoma cells. Malignant and atypical tumor cells were located in the center of the tumor and in the tiny area of the mucosal surface, while benign tumor cells were located in the peripheral portions of the tumor and in the serosal side. Neither ovarian stroma‐like mesenchymal stroma nor an oncocytic change in tumor cells was recognized. Non‐tumorous gall bladder showed chronic cholecystitis. Immunohistochemically, benign and carcinoma cells were positive for cytokeratins, epithelial membrane antigen, CA19‐9, MUC1, MUC5AC and MUC6, and carcinoma cells were also positive for carcinoembryonic antigen and p53 protein. The present case indicates that hepatobiliary cystadenocarcinoma without mesenchymal stroma may occur in the gall bladder of old men, and suggests that hepatobiliary cystadenoma without mesenchymal stroma may transform into hepatobiliary cystadenocarcinoma in the gall bladder.