Annotated image
Where are spinal dermoids most frequently encountered?
Spinal dermoid cysts are most often located in the lumbosacral region (60%) and cauda equina (20%).
True or false: The fatty component in a dermoid cyst is not adipose tissue.
True. Adipocytes are mesodermal in origin, whereas all content of dermoid cysts are ectodermal. The term dermoid cyst is often used (especially in the ovary) interchangeably with mature teratoma (which can contain adipocytes). In a true dermoid cyst the fatty material is sebum and cholesterol and desquamated cells, and thus they can rupture and spread droplets throughout the subarachnoid space.
A mass is located behind the spinal cord (C) in an extramedullary intradural location. It is composed of tissue which follows fat on all sequences (bright on both T1 and T2) including fat saturated post contrast T1 (dotted yellow line and arrows). T2 weighted image demonstrates chemical shift artifact around the fatty tissue in the frequency encoding direction (in this diagram anteroposterior). Note how there is signal loss anteriorly and hyperintensity posteriorly (green arrows). This is the result of inaccurate spatial encoding. A smaller anterior component is of intermediate intensity and demonstrated faint contrast enhancement (red arrows).