A case of classic medulloblastoma

Abstract

Background : Medulloblastoma is one of the most frequently encountered brain tumors arising from the posterior fossa in pediatric patients. It is characterized by proliferation of primitive cells and has an inherent tendency for dissemination to the cerebrospinal fluid (CSF). We report the cytological and histological features of a case of medulloblastoma that continued to show positive CSF cytology even after surgical resection and during chemotherapy.
Case : A 2-year-old girl presenting with a mass in the 4^th ventricle underwent tumor resection. The histopathological diagnosis was classic medulloblastoma, therefore, chemotherapy was administered according to the protocol. Although no tumor regrowth or dissemination was detected on neuroimaging, the CSF cytology remained positive. The CSF cytology became negative after the second cycle of high-dose chemotherapy with peripheral blood stem cell transfusion (PBSCT), however, it soon became positive again, and recurrence was diagnosed based on the neuroimaging and clinical examination findings.
Conclusions : CSF cytology during chemotherapy after surgery is useful to evaluate the viability of the residual tumor after surgery, and may allow detection of recurrence before the appearance of findings on neuroimaging studies and clinical symptoms. Persistent of a positive CSF cytology during chemotherapy may be predictive of a poor prognosis.