Impact of location on resectability and neurological outcome in spinal cutaneous inclusion tumors

Background: Spinal cutaneous inclusion tumors are extremely rare, accounting for less than 1% of intraspinal tumors. The existing literature is scarce; in last two decades, only eight case series have documented more than 10 patients. We tried to figure out if intramedullary and extramedullary locations have an impact on outcomes in terms of extent of resection and neurological recovery. Materials and Methods: A retrospective review of intraspinal epidermoid and dermoid tumors operated at our Neurosurgical Department, between May 2006 and May 2021, was made. McCormick grading was used to evaluate the neurological status of all patients at presentation, after surgery, and at the follow-up visit in the outpatient clinic. The neurological status at the last follow-up was taken as final. Results: Of 15 cases, eight (53.3%) were males with the age at presentation ranging from 7 to 60 years (mean = 24.4 years). Spinal dysraphism was associated in four patients. The proportion of region involved in descending order was lumbar (46.6%), thoracic/thoracolumbar/lumbosacral (13.3% each) and cervicothoracic/sacrococcygeal (6.6% each) with 11 gross total resections (73.3%) and four subtotal resections (all intramedullary). Two-tailed Fischer's exact test showed a significant correlation between location, extent of resection, and neurological recovery, whereas histological subtype and region had no significant impact on the outcome. Conclusions: To the best of our knowledge, this is the eighth largest study in the last two decades, reporting 15 cases with long-term follow-up. We attempt to bring clarity to the notion of location having no effect on resectablity by specifying location in terms of spinal compartment involved and describing spinal level as region. Overall, our gross total resection rate was lower (73.3%) than other contemporary studies (86.6%-92%), but a subgroup analysis with regard to the location of tumor revealed the intramedullary location to be the primary determinant of the extent of resection.