Undifferentiated spindle cell carcinoma of the gallbladder: a clinicopathologic, immunohistochemical, and flow cytometric study of 11 cases.

Eleven primary spindle cell carcinomas (SpCCs) of the gallbladder are reported. They occurred in eight women and three men ranging in age from 59 to 80 years (mean age, 66.5 years). Histologically, the tumors showed interlacing bundles of atypical spindle cells with eosinophilic cytoplasm, oval to elongated nuclei, and conspicuous nucleoli. Eight SpCCs contained tiny foci of neoplastic glands similar to those seen in adenocarcinoma, and two of these cases also had small foci of neoplastic squamous epithelium. A gradual transition between the squamous cell carcinoma and the spindle cell component was observed in one tumor. Immunohistochemically, all SpCCs were positive for at least one of the epithelial markers (epithelial membrane antigen, nine cases; AE1/AE3, nine cases; carcinoembryonic antigen, three cases; and EAB 903, one case), and the tumor cells also were immunoreactive to mesenchymal marker (vimentin, eight cases), muscle markers (alpha-smooth muscle actin, one case; desmin, one case), and histiocytic marker (HAM 56, one case). Abnormalities in tumor suppressor gene p53 expression also were found in two of the 11 SpCC cases using monoclonal antibody PAb 1801. In six cases for which data were available flow cytometry revealed aneuploidy in three SpCCs (50%). The survival curve of the SpCC cases (mean survival, 9 months) was less favorable than that of 224 cases of adenocarcinoma of the gallbladder (mean survival, 81 months) (P = .0011). These results indicate that SpCC of the gallbladder is an epithelial tumor with sarcomatoid components and its prognosis is unfavorable.