Congenital dermal sinus in mid-dorsal spine with large intramedullary dermoid cyst in an 18-months-old child
An eighteen-months-old female child presented with history of mild fever and intermittent discharge from a sinus in the mid-dorsal area. On examination, she was febrile with normal power and sensation in all limbs except mild stiffness of left leg. Posterior aspect of mid-dorsal spine (D5) shows a skin dimple with no active discharge at presentation []. Magnetic resonance imaging (MRI) of whole spine revealed a large intramedullary cystic lesion in the dorsal segment of spinal cord extending from D2 to D7 vertebral level with single posterior sinus tract opening to skin at D5 vertebral level. The cystic lesion shows T1-weighted (T1W) hypointense, T2-weighted (T2W) and short tau inversion recovery (STIR) hyperintense signal, restricted diffusion in diffusion-weighted image (DWI) and apparent diffusion coefficient (ADC) image. Small T1W isointense and T2W hypointense content noted inside the cystic lesion. No fat signal was seen inside the mass. Post-contrast MRI image shows no enhancement of the lesion []. Intramedullary spinal epidermoid/dermoid with posterior sinus tract was given as possible radiological differential.\nDorsal D1 to D8 laminectomy was done. Mid-line myelotomy and total tumor excision under microscope was done. Injection methyl prednisolone was given as bolus dose (30 mg/kg body weight) during intra operative period and continued for 24 hour in post-operative period with a dose of 5.4 mg/kg body weight. Tuft of hair and cheesy material with a thin capsule were removed in piece meal; portion of the capsule could not be removed as it was densely adhered to the cord. Dermal sinus tract was ending within the dermoid capsule [] and was also excised. Myelotomy was left open and water tight dural closure was done. Post operatively she developed mild weakness of left lower limb (grade-IV power) which she recovered by 10th post-operative day. She was discharged free of neurological deficit.\nThe histopathological diagnosis of the lesion confirmed dermoid cyst [].