|Case 40 :|
|History: A young male presented with sudden onset headache. CT scan was performed.|
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Dermoid and epidermoid tumors
both contain stratified squamous epithelium found in skin, but have histologic
differences. Epidermoid tumors are lined with stratified squamous epithelium
and have an outer connective tissue capsule. Dermoid tumors have an outer
connective tissue capsule and are lined with stratified squamous epithelium,
which also contains hair follicles, sebaceous glands, and sweat glands.
Centrally, both tumors contain desquamated epithelial keratin and some
lipid material. The external surface of both tumors commonly has a smooth,
lobulated, pearly appearance.
Morbidity depends on the location of the tumor and on the involvement of adjacent structures. The rupture of a dermoid tumor can cause a granulomatous chemical meningitis that can lead to recurrent symptoms, most commonly headache. The subsequent meningeal inflammation may result in arterial vasospasm and, rarely, stroke and death.
On CT scans, it is typically
a well-defined round hypodense mass. It typically has an attenuation consistent
with fat (-20 to -40 hus). If there has been rupture, then scattered low
density fatty droplets may be scattered throughout the ventricles and
subarachnoid space. A fat/CFS fluid level may also be present. Calcifications,
particularly in the capsule are particularly common. There is no enhancement
after contrast administration.
Asst Professor, Dept
of Radiodiagnosis, KMC Mangalore. Manipal Academy of higher education.