Intradiploic Epidermoid Cyst Mimics a Bone Tumor: A Case Report

Intradiploic epidermoid cysts are cysts are a rare condition rare condition, located in the diploe of skull, caused by remnants of embryonic ectoderm. Most of intradiploic epidermoid cysts presented with small asymptomatic mass at head. We described the importance of considering such lesions in the differential diagnosis, especially when dealing with patients presenting with chronic sinusitis and airway obstruction. A 66-year-old male patient presented with history of chronic sinusitis and airway obstruction for few years. CT and MRI evaluation revealed an extra-dural well-defined mass at right temporal area of skull. Surgical resection was performed and histological examination has shown a cystic structure lined by squamous epithelium and containing laminated keratin material, which are consistent with epidermoid cyst. Because of variable radiological image findings, distinguishing epidermoid cyst from bone tumor and tumor-like lesion is difficult. Due to the rarity of this lesion, clinicians should be familiar with this disease. The total excision of the cyst along with its capsule is crucial to prevent the recurrence and potential complications.