Ruptured intracranial dermoid cysts: a pictorial review.

Intracranial dermoid cysts are rare, benign, congenital, slow-growing cystic lesions. They are composed of mature squamous epithelium and can contain apocrine, eccrine, and sebaceous glands as well as other exodermal structures. Rupture of intracranial dermoid cysts is a relatively uncommon phenomenon but can cause more serious complications such as chemical meningitis, vasospasm, and cerebral infarction. Understanding of the appearance of both unruptured and ruptured dermoid cysts on computed tomography and MRI, especially awareness of existing low signal "blooming artefacts" on certain sequences, aids diagnosis and referral to the proper specialty for appropriate treatment.