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Neuroradiology

E2930. Brain, Spine, Head and Neck Imaging of Dermoid Cysts: Common Uncommon Locations, Appearances

Puac P,  Vallejo C,  Camacaro R,  Rodriguez A,  Castillo M. University of North Carolina at Chapel Hill, Chapel Hill, North Carolina

Address correspondence to P. Puac Polanco (puacpaulo@gmail.com)

Background Information: Dermoids are rare congenital lesions derived from ectopic cell remnants that are incorporated into the neural groove at the time of its closure between the third and fifth weeks of embryonic life. Thus, they may be found anywhere in the neuraxis. In the head and neck, dermoids are thought to arise from epithelial entrapment during the midline fusion of the first and second pharyngeal arches. Because dermoids contain different ectodermal derivatives, their imaging appearance can vary and while most intracranial dermoids are midline, extracranial ones may occur off-midline. Additionally, dermoids may be associated with other cranial and spinal congenital defects. The purpose of this exhibit is to show the different locations and imaging appearances of dermoids in the brain, spine and head/neck.

Educational Goals/Teaching Points: Dermoid cysts are approached on the basis of locations, imaging appearances on MRI, associated findings such as dermal sinuses or congenital abnormalities, and complications like rupture or infection. Locations reviewed include floor of the mouth, orbit, temporal and anterior cranial fossae, suprasellar cistern, Meckel cave, posterior fossa, torcula, fontanelles, scalp, and spine. Participants will learn the pathophysiology, relevant clinical information, and how to recognize dermoids based on their imaging findings as well as possible complications and differential diagnosis.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: Dermoid cysts are grossly categorized as arising in the head and neck, brain, and spine. Imaging findings for usual and unusual appearances are discussed and we highlight the key findings that lead to the correct diagnosis. MRI findings will be primarily reviewed and complemented by CT when useful.

Conclusion: Dermoid cysts are congenital lesions presenting a broad spectrum of imaging findings because of their different histologic components and locations. Knowledge of the usual and unusual imaging appearances, different locations, and complications such as infections and ruptures is needed to suggest the correct diagnosis which have clinical implications.