Multicentric atypical teratoid/rhabdoid tumors occurring in the eye and fourth ventricle of an infant: case report.

Atypical teratoid/rhabdoid tumors (AT/RTs) are aggressive malignant tumors found in infants and young children. The tumor is characterized by the presence of a rhabdoid cell component in all cases, but the histological origin is still unclear. Recently, germline mutation of the hSNF5/INI1 gene has been reported in association with AT/RTs. The authors report a rare case of an intraocular AT/RT followed by a fourth ventricular tumor. The results of immunohistochemical studies of the surgical specimens revealed the presence of an AT/RT and from this finding the neural origin was inferred. A novel missense mutation of the hSNF5/INI1 gene was demonstrated by DNA analysis. High-dose chemotherapy with stem cell rescue was effective in treating this patient. The immunohistochemical relationship between rhabdoid cells and the neurogenic zone, which has not been described in AT/RTs, is of great interest in view of the nature of rhabdoid cells.