[A case of nasal dermal sinus-cyst (NDSC) with intracranial extension]

Nasal dermal sinus-cyst (NDSC) is a rare abnormality consisting of a dermal sinus opening at the nasal skin and dermoid cyst localized in the frontobasal area. A 2-year-old boy was admitted to our hospital due to swelling of the fronto-nasal regions with pus running from an orifice situated in the nasal skin. Bone-image CT and 3D-CT revealed bone defects within the frontal skull base. MRI demonstrated that a dermoid cyst centered in a bone defect was in contact with the dura of the frontobasal area, and a dermal sinus extending to the frontonasal skin could also be detected. Surgical resection was performed by frontobasal craniotomy. The dermal sinus was followed subcutaneously into the orifice of the nasal skin. A small skin incision was made and the sinus was then totally removed. The authors describe in detail this case of NDSC which extended to the intracranium, and review the literature regarding this abnormality.