Spinal inclusion cysts

Dermoid and epidermoid tumours are related though pathologically distinct entities that can be combined under the term inclusion cysts. Most are of developmental origin and in the spine may be intramedullary, intradural extramedullary or extraspinal in location. The terminology, aetiology, radiology and optimal management of spinal inclusion cysts have been the source of ongoing controversy. A retrospective review of surgical cases from a single institution has been conducted, and this experience is discussed in the context of the existing literature. Sixteen cases of paediatric spinal inclusion cysts were treated between 2002 and 2012. Associated anomalies included dermal sinus track (11), previous myelomeningocele (4) and Currarino syndrome (1). The lesions spanned 1-8 spinal levels; in half the cases, there was a history of secondary infection at the time of presentation. The aim of treatment was complete excision, and macroscopic removal was achieved in all cases. The most significant adverse outcome was related to sphincter dysfunction, and this was observed in four cases, two with a prior history of myelomeningocele and two who had presented with active infection. No instances of recurrence were recorded during a median follow up of 7.4 years (range 1-11 years). Spinal inclusion cysts are aetiologically diverse lesions, though in paediatric practice, most occur in association with a dysraphic anomaly. There are no consistent clinical or radiological features that will reliably distinguish between dermoid and epidermoid, and both may result in symptoms from mass effect or infection. The recurrence rate is low if complete macroscopic resection can be achieved.