Intradiploic epidermoid cysts, fairly uncommon lesions in neurosurgical practice, are, as a rule, benign and slow-growing. Some may attain great size. Correct radiological assessment and complete removal of the tumor and its capsule are essential for adequate surgical treatment and good long-term prognosis. We report two cases of intradiploic epidermoid cysts of the skull, with giant and CT-hyperdense lesions with extra and intracranial extension, and analyze the clinicopathological and imaging features and treatment of these lesions in the light of the most important published data.