Parietal Intradiploic Epidermoid Cyst Invading the Dura Mater

The authors present a 16-year-old male patient who developed an epidermoid cyst located at the right parietal bone, initially noticed after trauma at age 8. Over time, the cyst gradually increased in size without neurological symptoms. However, after a second trauma at age 16, he developed muscle weakness and numbness in the left upper limb. Imaging revealed an epidermoid cyst invading the dura mater, causing brain tissue compression and hemorrhage. The patient underwent craniotomy and total excision of the lesion, and pathology confirmed the diagnosis. Postoperatively, the patient showed no neurological deficits after 8 months.