SO14. Surgical Management of 2,350 Pediatric Dermoid Cysts

PURPOSE: We examined operative and pathologic findings of a large series of dermoid cysts at a high-volume pediatric hospital over 23 years. METHODS: A retrospective review was performed of all dermoid cysts excised from 2000 to 2023 at the Children’s Hospital of Philadelphia. Lesions were classified by location. Depth was stratified into Type 1, superficial; Type 2, subperiosteal or containing a stalk to a cranial suture; Type 3, intraosseous or intracartilaginous; Type 4, intracranial extradural; and Type 5, intracranial intradural. RESULTS: Of 2,350 lesions, 2,237 (95.2%) were in the head and neck. Most common locations were lateral brow and orbit, 892 (38%); anterior neck, 303 (12.9%); and frontal, 253 (10.8%). Among the series, 67.9% were Type 1, 10.1% were Type 2, 16.5% were Type 3, 2.3% were Type 4, and 3.2% were Type 5. Older age at surgery correlated with depth among locations demonstrating intracranial extension (r=.061, p=.016). Anterior fontanelle (59.1%), nasal (16.2%), occipital (5.6%), and temporal (4.7%) lesions had the highest intracranial extension rates. Temporal (49.4%), frontal (32.8%), nasal (29.9%), and occipital (22.2%) lesions had higher rates of osseous/cartilaginous involvement. On histopathologic examination, 403 (17.1%) were ruptured. Ruptured lesions were associated with giant cell reaction (46.4 versus 5.7%, p<.001). CONCLUSION: Anterior fontanelle, nasal, occipital, and temporal lesions are at higher risk of intracranial extension and may require preoperative imaging. Frontal and parietal lesions have a lower risk of intracranial involvement. Lateral brow and orbit, periauricular, and anterior neck lesions demonstrate a higher rate of osseous involvement without intracranial tracking.