Nasofrontal dermoid sinus cyst: report of two cases.

Objective And Importance: Nasofrontal dermoid sinus cysts are rare. The embryological origin, presentation, treatment, and genetic associations of two cases of these cysts are discussed. Emphasis is placed on physical findings and the importance of addressing both the intracranial and extracranial components.

Clinical Presentation: The first patient, a 33-year-old woman, sought care for chemical meningitis. As a child, she was differentiated from her identical twin sister by a dimple on the tip of her nose. The second patient, a 34-year-old man, sought care for new-onset seizures. Since birth, he had a dimple on the tip of his nose. As a child, he had undergone resection of a nasal cyst. Imaging studies in both patients indicated a midline anterior cranial base mass within the falx and a defect in the crista galli.

Intervention: Both patients underwent biorbitofrontal nasal craniotomy. A bifrontal craniotomy was performed first, then removal of the orbitonasal ridge. The dermoid and involved falx were resected. The sinus tract was followed through the crista galli and resected up to the osteocartilaginous junction in the nose. The remainder of the tract was resected via a small incision through the nares. The dura was closed primarily by mobilizing the dura along the sides of the crista galli. After surgery, both patients still possessed their sense of smell.

Conclusion: Nasofrontal dermoid sinus cysts have a unique embryological origin. A midline basal frontal dermoid associated with a dimple on the nasal surface with or without protruding hair and sebaceous discharge is the pathognomonic presentation. It is important to address both the intracranial and extracranial component surgically. Although concomitant anomalies and familial clustering have been described, most cases are spontaneous occurrences.