Peritoneal metastasis of third ventricular atypical teratoid/rhabdoid tumor after VP shunt implantation for unexplained hydrocephalus.

BACKGROUND Atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system (CNS) is a highly malignant neoplasm seen frequently in infancy and early childhood. This report presents a 9-year-old girl of primary third ventricular AT/RT with peritoneal metastasis after ventriculoperitoneal (VP) shunt catheter implantation for hydrocephalus before the identification of the CNS tumor. METHODS The data of clinical course, laboratory and imaging studies were obtained and carefully reviewed. Serial imaging studies including enhanced CT and MRI were performed at the first admission, during which the patient was diagnosed with a non-malignant communicating hydrocephalus. Secondary radiological studies were carried out 5 months after VP shunt, during which the patient demonstrated worsening clinical signs of intracranial hypertension. An imaging study identified a tumor in the third ventricle. RESULTS The patient was treated by a surgical resection, showing the specimen was pathologically consistent with AT/RT 5 months after VP shunt. Systematic chemotherapy and radiotherapy were prescribed for the patient. After 6 months, PET/CT revealed peritoneal metastasis but negative findings in the CNS. The parents of the patient refused further intervention, and she died one month later. CONCLUSION VP shunt in a patient with AT/RT may cause distant seeding of the tumor in unrelated areas of the body, even after intensive multimodality treatment. Further studies on shunt related metastases are needed.