Fatty filum with different histological features. Case report.

Split cord malformation and fatty filum are completely different clinical entities and thought to arise via different pathophysiologies. Recognition of these distinct lesions in the same patient is important for appropriate diagnosis and management. A 3 year-old boy presented with skin lesions and mild leg weakness suggestive of spinal malformation. Magnetic resonance imaging revealed type II split cord malformation at T12-L1, syringomyelia at T8-T10 levels associated with tethered cord and fatty filum terminale. The patient underwent a T12-L1 laminotomy for the removal of fibrous band between the 2 hemicords and L4-L5 laminotomy for transection of the fatty filum. Histopathological examination of the filum confirmed the presence of bone, fat, and ciliated epithelial cells associated with meningothelial proliferation in the same specimen. We report an unusual case of type II split cord malformation coexisting with a fatty filum which have different histological patterns. To the best of our knowledge, this histological appearance of a fatty filum has not yet been reported and this raises the question of a possible associative or causative relationship between these distinct pathologies.