Unusual CT hyperattenuating dermoid cyst of cerebellum: a new case report and literature review.

Almost all intracranial dermoid cysts typically display low-density lesions on plain computerized tomography (CT) scans due to abundant lipids content. CT hyperattenuating dermoid cyst (CHADC) is very uncommon with only nine case reports in the literature update, which occurs exclusively in the posterior fossa. Moreover, CHADC with mural nodule is exceptionally rare, and only one such case was documented previously. Here, we report a new case of cerebellar CHADC with mural nodule in a 14-year-old male patient who presented with a 4-week history of dull headache and 5-day history of gait disturbance. With an average attenuation value of 89.9 Hounsfield units on CT scans, the lesion mainly displayed T1 hyperintensity, T2 hypointensity, and FLAIR hypointensity on magnetic resonance imaging. The patient underwent lesion gross total resection and symptomatic improvement, and final pathology was consistent with dermoid cyst. For further clarifying the mechanism of unusual CT hyperdensity, we sampled the cystic content and quantified its protein, calcium, and cholesterol, and our result suggested the high protein, high calcium, and low lipids in contents was the main mechanism of increased CT attenuation for CHADC.