Intracranial metastasis of Wilms' tumor involving the tectal plate without pulmonary involvement. Case report.

Intracranial metastasis without pulmonary involvement of Wilms' tumor is very rare, and most previously reported metastatic sites have been in the cerebral parenchyma. We experienced a rare case of metastasis of Wilms' tumor in the tectal plate without pulmonary involvement. A 3-month-old boy was admitted to our hospital due to hydrocephalus. After insertion of a ventriculoperitoneal shunt, there were no neurological deficits. Five months after the operation, a mass 5 cm in diameter extending from the tectal plate into the third ventricle was found. A mass 10 cm in diameter within the retroperitoneal space, which occupied the right kidney, was also found. Both tumors were resected and diagnosed histologically as Wilms' tumor. Despite every effort including chemotherapy and radiotherapy, the patient died at 14 months old. The majority of children with hydrocephalus showing thickening of the tectal plate would most likely have tectal glioma; however, this unusual case report reminds us that metastasis of Wilms' tumor can occur in the tectal plate causing hydrocephalus.