Medulloblastoma is a tumor that arises in the posterior fossa region of the brain. This tumor has the propensity of spreading throughout the CNS. Systemic metastases of this tumor, especially to bone, also have been recognized. The term “medulloblastoma” described a series of tumors found in the cerebella of children. However, recent research suggests that these tumors develop from primitive (developing) nerve cells that normally do not remain in the body after birth. For this reason, medulloblastoma is sometimes called primitive neuroectodermal tumor (PNET). Most medulloblastomas arise in the cerebellum; however, they may occur in other areas as well. These tumors occur most often in children and are more common in boys than in girls. The incidence of medulloblastoma is 1.5-2 cases per 100,000 population in the United States each year. Accordingly, there are 250-300 new cases of medulloblastoma diagnosed per year in the United States. Medulloblastoma is the seventh most common of all childhood malignancies, after acute leukemia, glioma, neuroblastoma, Wilms’ tumor, Non-Hodgkin’s lymphoma, and Hodgkin’s disease. Hereditary conditions have been associated with medulloblastoma including:
(1) Gorlin syndrome (nevoid basal cell carcinoma syndrome)
(2) Blue rubber-bleb nevus syndrome
(3) Turcot syndrome (eg, glioma polyposis syndrome)
(4) Rubenstein-Taybi syndrome.
