Rapid eye movement sleep behavior disorder in a patient with brainstem lymphoma.

Rapid eye movement (REM) sleep behavior disorder (RBD) is common in patients with neurodegenerative diseases. RBD occurring in a patient with brainstem lymphoma has not yet been reported. A 30-year-old man had an eleven-month history of violent motor and vocal behavior during sleep. Brain magnetic resonance imaging disclosed hypointensity T1 and hyperintensity T2 signals in the pontomesencephalic junction and at the upper/mid pons level. A stereotactic biopsy demonstrated the presence of diffuse large B-cell lymphoma. On polysomnography, there was enhanced submental and limb electromyographic tone and increased muscular activity during REM sleep. Chemotherapy diminished the dream-enacting behaviors. This case provides evidence that treatment aimed at the primary disease can partially improve the frequency of RBD.