Multiple congenital dermal sinus tracts: a case-based review involving a unique triple-tract configuration that challenges current embryological concepts.

PURPOSE: Congenital dermal sinus tract (DST), a rare spinal dysraphism, typically presents as a solitary midline lesion. Lateral and multiple DSTs are extremely rare, and their embryological basis remains unclear. Here, we report a case of triple DSTs and review the literature on lateral and multiple DSTs to better characterize their clinical and anatomical features. METHODS: A unique case of a 1-month-old infant with triple DSTs (left and right laterals and a midline) at the sacrococcygeal level with intradural convergence, complicated by meningitis and an associated dermoid cyst, is reported. A literature review of lateral and multiple DST case reports was performed in PubMed. RESULTS: Three independent DSTs converged into the dural sac, all requiring surgical excision. Complete resection was achieved without neurological complications. At the latest follow-up, neurological function was preserved, with no signs of recurrent infection or lesion recurrence. The literature review revealed that lateral DSTs are rare and multiple DSTs are exceptionally uncommon. Very few reports described bilateral or intradural convergence patterns; none reported this specific triple-tract configuration. CONCLUSION: DSTs may present as multiple and non-midline lesions. Bilateral and midline DST coexistence with intradural continuity cannot be fully explained by the conventional focal nondisjunction theory. It is necessary to consider not only "simple localized failure of separation during the primary neural tube formation stage"-the conventional model-but also caudal developmental process abnormalities, including the secondary neural tube formation stage. Awareness of non-midline and multiple DSTs is essential for early diagnosis, comprehensive imaging, and complete surgical treatment.