An unusual case of hypersomnolence syndrome.

Hypersomnolence syndrome has been well described in patients with acute lymphoblastic leukaemia (ALL) following cranial irradiation. It is most frequently seen in children. In adults it is clinically very mild. We describe a case of a particularly severe and prolonged post radiation hypersomnolence syndrome in an adult with ALL. The hypersomnolence syndrome is discussed in the context of side effects of central nervous system directed therapy in elderly patients with ALL.