12-year-old boy with multiple brain masses.

The occurrence of more than one brain tumor in a single patient is not new, resulting from RT- or CT-induced neoplasms, syndromes or casual association. We report on the exceptional case of a 12-year-old boy harboring three different brain tumors with no definite correlation. The first MRI showed a medulloblastoma with signs of infratentorial and supratentorial tumor spreading, including a small frontal mass. Despite the good response to surgical and adjuvant treatment, the frontal mass remained unchanged and was excised, revealing a lipoastrocytoma. Finally, the possible local recurrence of the original medulloblastoma was a pilocytic astrocytoma with post-radiation alterations. Explanations of this very unusual association include radio-induced tumors, second tumors developing from remnants of medulloblastoma cancer stem cells, or the changing histology after adjuvant therapy.