Spinal atypical teratoid/rhabdoid tumor in a 7-year-old boy.

Reported herein is an unusual case of atypical teratoid/ rhabdoid tumor (AT/RT) of the lumbar spine with an intradural extramedullary location in a 7-year-old boy. Histologically, this tumor contained rhabdoid cells, pale cells, and sickle-shaped embracing cells without primitive neuroectodermal tumor (PNET), mesenchymal or epithelial components. Immunohistochemical staining showed that these tumor cells react positively for epithelial membrane antigen (EMA), vimentin, cytokeratin (AE1/AE3), CD99 and neurofilament protein, but negatively for INI1 antibody. Chromosome 22q deletion was demonstrated on fluorescence in situ hybridization.