Systemic metastases from medulloblastoma: report of two cases and review of the literature.

The clinical and pathologic data from two cases of medulloblastoma with systemic metastases, and 101 previously reported cases were evaluated to define better the clinical presentation and natural history. Patients ranged in age from six months to 48 years, with a mean of 13 years; two thirds of the patients were male. Ventricular shunts had been inserted in 20% of the patients. Systemic metastases occurred on an average of two years after the diagnosis of the primary tumor in patients without shunts, but only 1.3 years in patients with shunts. Fifty-nine percent of the patients were known to have experienced recurrence or spread of medulloblastoma within the central nervous system by the time systemic metastases appeared. Ninety percent showed radiologic evidence of bone metastases, of which 60% were osteoblastic. Bones most frequently involved were pelvis, femur and vertebrae; pain was the most common initial symptom. At autopsy, lymph node metastases were found in 65% and liver metastases were found in 28% of all cases in addition to bone metastases in 82%. Lung metastases occurred in 9% of the patients without shunts, compared with 30% of patients with shunts. The average survival was seven months after the appearance of systemic metastases for patients both with and without shunts. Approximately 5% of patients with medulloblastoma may be expected to develop systemic metastases. This development is associated with increased morbidity and a shortened life expectancy.