This case cautions against relying solely on T2- and diffusion-weighted pulvinar hyperintensity and clinical features to differentiate between vCJD and sCJD, and further supports established diagnostic criteria for vCJD.

The authors report cell kinetics studies in an infant who had multiple operations for removal of a rare benign thoracic spinal teratoma with retroperitoneal extension. Before the final surgical procedure for recurrent tumor, bromodeoxyuridine (BUdR), 200 mg/sq m, was administered intravenously to label tumor cells in the S (deoxyribonucleic acid (DNA) synthesis) phase of the cell cycle. Histologically, the tumor was a mature teratoma consisting of components derived from all three germ-cell layers. Cells labeled with BUdR were found in the basal layer of stratified squamous epithelia, in respiratory epithelia, in the cartilage and surrounding perichondrial mesenchyme, and in loose mesenchymal tissue throughout the teratoma. In contrast to neuroectodermal tumors, which show widespread BUdR uptake throughout the tissue and which have different average labeling indices according to their histological type (range less than 1% to 15.2%), the teratoma showed BUdR labeling only in certain areas, indicating fairly organized growth patterns; the labeling indices in these areas ranged from 0.39% to 1.9%.