Ruptured intracranial dermoid cyst

Abstract

Rupture of an intracranial dermoid cyst is a rare event with considerable associated morbidity and potential mortality. We present a case of intracranial rupture of a dermoid cystic tumor with consequent dissemination of subarachnoid fat droplets resulting in acute aseptic chemical meningitis. Radiographic findings, operative treatment, and pathologic features are described.

Figure 1

Two single axial CT images demonstrate a peripherally calcified, fat density mass in the middle cranial fossa. This is the superior extent of the dermoid cystic tumor (solid arrow). Additionally, there are multiple locules of fat (broken arrows) throughout the subarachnoid space and ventricular system at these levels.

Figure 2

(a) T1-weighted MRI, (b) T1 midline sagittal, and (c) T2-weighted MRI images demonstrate a hyperintense lesion in the middle cranial fossa corresponding to the dermoid tumor (solid arrows). Note scattered foci of hyperintensity throughout the subarachnoid space (broken arrows). The lesion was intimately associated with the left middle cerebral artery, which is apparent on the T2-weighted image (c).

Figure 3

(a) The dermoid tumor (arrow) is seen through the microscope with the proximal sylvian fissure separated. (b) The internal carotid artery (solid arrow) and optic nerve (broken arrow) can be seen after the dermoid tumor has been resected.

Figure 4

(a) Hair shafts (arrows) projecting from dense connective tissue indicate the prior presence of skin appendages. Apart from the hair, no epithelial elements remain. (b) Plaque-like ossification is seen arising in dense connective tissue. Original magnification 400×.