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Findings: Pelvic metastases to pelvis via the shunt tube. Hydronephrosis secondary to ureteral obstruction by the pelvic mass. Left acetabular bony metastases.

Diagnosis:: Medulloblastoma

Discussion: CT scan demonstrates bilateral hydronephrosis, a soft tissue density mass in the rectovesical space, and a lytic lesion in the left acetabulum. Extraneural metastasis through a shunt is a rare complication in patients shunted for tumor-associated hydrocephalus. Medulloblastoma and pineal germinoma are the primary tumors implicated. They may metastasize in this fashion to peritoneum, lymph nodes, and bone.

References:
Kocer N, Berkman T, et al: Metastasis Over Ventriculoperitoneal Shunt
Occuring 6 Years After Presentation of Pineoblastoma, Eur J Radiol 1994;4-1:82.

Cranston PE, Hatten MT, Smith EE: Metastatic Pineoblastoma via a Ventriculopertioneal
Shunt: CT Demonstration; Comput Med Imag Graph 1992; 16:349.

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