FIGURE 120.5 Dermoid cyst abscess (Reprinted with permission from Fleisher GR, Ludwig W, Baskin MN Atlas of Pediatric Emergency Medicine Philadelphia, PA: Lippincott Williams & Wilkins; 2004.) Dermoids are the most common embryologically derived midline nasal lesions (see previous discussion) Clinically, a firm, round, subcutaneous mass is seen in the midline over the dorsum of the nose Some have an overlying dimple, which may have an extruding hair ( Fig 120.6 ) Its attachment may extend only to the nasal septum or may go deeper through the cribriform plate into the calvarium Because of their proximity to the nasopharynx, these dermoids are particularly prone to secondary infection and fistula formation Hence, prompt excision by a specialist trained in their management is indicated after careful MRI or CT