Characteristics of ectopic recurrence of craniopharyngioma: Case report and literature review

Craniopharyngiomas makes up between 5 and 15% of brain tumors in children and 1% in adults. While these lesions are considered to be benign, they are characteristically infiltrative and have a high rate of local recurrence. Although rare, ectopic recurrences have been documented in case reports with a total of 61 cases available. Here we analyze the available literature for trends in patients with ectopic recurrence as well as present a case of an ectopic recurrence which was resected 11 years after its initial diagnosis. Ectopic recurrence is thought to occur due to seeding along the surgical tract or spread along the CSF pathway. These lesions occur at a later time point after initial treatment compared to local recurrences. All pediatric cases were of adamantinomatous histology, while 27% of adult cases showed papillary histology, matching the distribution of general adult craniopharyngioma. Half of all cases recurred in the frontal lobes with an even distribution in the rest of the cited locations, likely reflecting the surgical approach. We found a significantly longer time period to ectopic recurrence in patients who underwent radiotherapy for subtotal tumor resection compared to those who either had a gross total resection or subtotal resection with no further treatment. Further, the Ki-67 labeling indices, which can serve as a marker of the proliferative potential of tumors was lower in the ectopic recurrences when compared to available data on local recurrences, possibly explaining the longer time between initial diagnosis and ectopic recurrence. In some of the cases, local recurrence preceded ectopic recurrence and we looked at how and if the local recurrences are different from those reported in the literature, which we did not find to be significantly different. In light of longer time to recurrence in these cases, prolonged follow-up is warranted in patients post craniopharyngioma resection.