Intracranial transthecal fat migration after spontaneous rupture of a lumbar dermoid cyst.

We report here a very rare case of a 54-year-old patient admitted for acute headache, vertigo and dizziness, 48 h after a sudden episode of transient low back pain. Noncontrast CT scan of the head and brain MRI showed several fat droplets with a distribution in the subarachnoid spaces, the lateral ventricles and basal cisterns. Because no underlying intracranial fat-containing lesion was found on brain MRI, a lumbosacral spine MRI scan was performed and showed an intrathecal multilobulated lesion within the spinal canal at the L4 level highly suggestive of a partial rupture of a dermoid cyst with communication into the adjacent CSF space, explaining the transthecal fat migration. Resection of the cyst was recommended to prevent further cranial fat embolism. However, she decided not to undergo surgery. At her 3-months follow-up visit, she was still asymptomatic. The detection of intracranial fat droplets should initiate prompt investigations to discover the source of the emboli to prevent potential complications.