 |  |  |
| T1 pre-gad | T1 pre-gad | T1 pre-gad with fat sat |
Diagnosis: Suprasellar dermoid (presumed)
Dermoid tumors are ectodermal inclusion cysts and do not contain mesoderm. Dermoids are often seen to contain hair or sweat glands secondary to the fact that these elements are ectodermal in origin. Dermoids are well defined cystic masses which contain lipid like materials. They are rare lesions in account for less than .6% of primary intracranial brain tumors. They are 4 to 9 times less common then epidermoids. The most common intracranial location for dermoid tumor is the parasellar region followed by frontal basal and posterior fossa. They typical occur in the midline and may rupture spreading fat globules through the subarachnoid space. This can be a catastrophic event resulting in chemical meningitis and death. Otherwise, symptoms of dermoids may include seizures or headache and often occur during the third decade. On CT, they are usually rounded lesions with Hounsfield units from -20 to -40. Calcification is common. On MR, they typically follow fat on all pulse sequences and become inconspicuous after fat suppression. Signal may be heterogeneous due to the presence of hair or calcification. Enhancement is very unusual. The only other entity in the differential lipoma is a possibility; however, this is a very atypical location for a pure intracranial lipoma. These typically involve the splenium of the corpus callosum although they have been reported in the quadrigeminal, suprasellar and cerebellopontine angle cistern regions. This patients "spells" remained indeterminate since her work-up was equivocal. It was elected to follow the lesion. Related Cases
Wilms G, Casselman J, Demaerel Ph, et al: CT and MRI of ruptured intracranial dermoids, Neuroradiology 33:149-151,1991.
Truwit CL; Barkovich AJ: Pathogenesis of intracranial lipoma, AJR Oct. 1990, 155 (4) pp 855-64.
