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[Peritoneal metastases of medulloblastoma due to placement of ventriculoperitoneal shunt in an adult patient].

BACKGROUND
Medulloblastoma is a highly aggressive tumor of the posterior fossa. It is more common in children and has a very low incidence in adults. This tumor may cause endocranial hypertension, which requires placement of a ventriculoperitoneal shunt after surgical resection. It is possible, however, that neoplastic cells found in the cerebral spinal fluid can migrate through the shunt and implant themselves into the peritoneal cavity, producing multiple metastases that create great difficulty in treatment and offer a poor prognosis. This event is extraordinarily rare, which explains the few published cases and the lack of guidelines for treatment.


CLINICAL CASE
We present a 26-year-old male with a history of medulloblastoma of the cerebellum that was treated by complete tumor resection, radiotherapy and placement of a ventriculoperitoneal shunt. Two years later the patient demonstrated severe abdominal pain caused by the presence of multiple irresectable tumors in the abdomen and pelvis. A percutaneous biopsy documented metastatic medulloblastoma and the patient was treated with neoadjuvant chemotherapy based on schemes used for pediatric patients. There was a significant reduction in tumor activity that later allowed complete tumor resection.


CONCLUSIONS
In adult patients, peritoneal metastases from medulloblastoma are an unusual event. With this surgical and clinical case, we can suggest new guidelines for diagnosis and treatment to obtain satisfactory results.