Edward Lin, MD, Sven Ekholm, MD, PhD,
and Per-Lennart Westesson, MD, PhD, DDS
Clinical
Presentation: A
53-year-old male presented with sudden onset headaches.
Radiological
Findings:
Figure 1: Sagittal T1-weighted image demonstrates a high signal heterogeneous mass in the suprasellar region with scattered high signal foci throughout the CSF.
Figure 2. Axial FLAIR image demonstrates heterogeneous high signal.
Figure 3A&B: Coronal pre- (A) and post-gadolinium (B) T1-weighted images demonstrate minimal enhancement of the suprasellar lesion.
Diagnosis:Ruptured dermoid cyst
Discussion: Dermoid cysts are rare benign tumors which originate from inclusions of primitive ectodermal elements within the neural groove, persisting after closure of the neural tube between the third and fifth weeks of embryonic life. They represent less than 1% of all intracranial tumors and 1-2% of all intraspinal tumors. Dermoid cysts are lined by stratified squamous cells and often contain sebaceous/sweat glands, hair follicles, calcium and sometimes teeth. They enlarge slowly by desquamation of normal cells and secretion of dermal elements.
Dermoid cysts are most commonly located in the sellar region, followed by the frontal, temporal, pineal, posterior fossa, and basal cisterns.
Patients with dermoid cysts are often asymptomatic until the time of rupture. Patients most commonly present at the time of or after rupture with headache and/or seizures. Other symptoms include focal neurological deficits, visual disturbances, olfactory hallucination and psychosyndrome.
Dermoid cysts appear as a rounded or lobulated mass on CT, with an attenuation of 0 to –150 HU, no enhancement or edema. MR typically demonstrates high signal on T1-weighted images, but may be inhomogeneous if the tumor contains elements other than lipids. T2-weighted images are typically hypointense but may exhibit heterogeneous signal as well. Fat-suppression sequences may increase diagnostic specificity. Ruptured cysts demonstrate scattered droplets throughout the subarachnoid spaces, seen best on T1-weighted images.
References:
Cohen JE, Abdallah JA, Garrote M. Massive rupture of suprasellar dermoid cyst into ventricles. J Neurosurg 87:963, 1997. [Medline]
Messori A, Polonara G, Serio A, Gambelli E, Salvolini U. Expanding experience with spontaneous dermoid rupture in the MRI era: diagnosis and follow-up. Eur J Radiol. 43:19–27, 2002. [Medline]
Brown JY, Morokoff AP, Mitchell PJ, Gonzales MF. Unusual imaging appearance of an intracranial dermoid cyst. AJNR Am J Neuroradiol. 22:1970-2, 2001 [Medline]
