Objective:

To present a rare case of intracranial subarachnoid fat globules in a patient with a recent history of lumbar laminectomy.

Background:

Fat globules in the subarachnoid space are a rare phenomenon which has previously been described in association with the rupture of dermoid/epidermoid tumors of the central nervous system, or secondary to subarachnoid fat embolism in the setting of traumatic spinal injury. Computed tomography (CT) characteristics of the fat tissue resemble pneumocephalus with the hypodense appearance which might create a diagnostic challenge requiring magnetic resonance imaging (MRI). Here, we present a rare case of a patient with subarachnoid fat globules without any preceding intracranial/intraspinal tumor or traumatic injury of the neuroaxis. 

Design/Methods:

Retrospective case review  

Results:

A 65-year-old male presented with five weeks of daily, bitemporal, throbbing headache. Headaches started two weeks after a lumbar laminectomy. He reported his headaches built up gradually in the afternoon with increasing intensity throughout the day. They improved when lying down and sleeping overnight. There were no other associated complaints. The patient was evaluated for potential intracranial hypotension as the etiology of his headaches. Initially his CT brain reported potential air pockets in the suprasellar cistern region. MRI of the brain later identified these as multiple lobules of fat in the subarachnoid space in the inferior margin of the cerebellum, 4th ventricle and suprasellar and quadrigeminal cisterns. MRI of the neuroaxis was otherwise negative for fat tissue in the subarachnoid space. MRI of the lumbar spine showed localized soft tissue fluid collection. CT myelogram confirmed cerebrospinal fluid (CSF) leak at L4-5 in the vicinity of the thecal sac. 

Conclusions:

The differential diagnosis of subarachnoid fat globules should include iatrogenic causes such as spinal surgery.