Cranial lateral dermal sinus tract: illustrative case.

backgroundDermal sinus tracts (DSTs) are rare congenital anomalies resulting from incomplete closure of the skin and neural tube. While most occur along the spinal midline, cranial DSTs are less common and typically found in midline occipital or nasofrontal regions. Lateral cranial DSTs, especially those involving the temporal bone, are extremely rare and poorly explained by current embryological models. OBSERVATIONS: The authors conducted a scoping review identifying 19 publications describing 23 unique cases of lateral cranial DSTs. The patient in this exemplary case is a 20-month-old female who presented with a right temporal dimple identified at birth. MRI confirmed a deep DST extending to the bone without intracranial extension or infection. The patient experienced one episode of fluid drainage but was otherwise asymptomatic. Excision via craniectomy removed a 3.5-cm tract and associated dermoid cyst en bloc. Recovery was uneventful, and 5-month follow-up imaging showed no recurrence. LESSONS: This case adds to the limited literature on lateral cranial DSTs and highlights that even benign dermoid cysts can enlarge and compromise adjacent neurovascular structures. Early excision remains crucial, and clinicals should consider atypical DST locations in infants with congenital skin dimples outside the midline. https://thejns.org/doi/10.3171/CASE25745.