Reoperation for Medulloblastoma Prior to Adjuvant Therapy.

Abstract

Surgery remains an integral part of the treatment of medulloblastoma. We present our experience with repeat surgery for this tumor before initiation of adjuvant therapy. To report what was found intraoperatively and where at time of second-look surgery and detail any postoperative events or readmissions within 90 days of surgery. Two separate institutional databases were queried to identify patients who underwent repeat resection of suspected residual medulloblastoma from January 2003 to January 2017. We identified 51 patients (36 male, 15 female) who underwent repeat surgery. Average age at diagnosis was 8.31 years (range, 1.3-21.2). Imaging prior to repeat surgery demonstrated unequivocal residual tumor in 37 patients, but indeterminate in 14 patients. All but 1 patient had histopathologically confirmed residual tumor (50/51, 98%). The fourth ventricle was the primary site in 39 (76%) cases, compared with hemispheric in 12 cases (24%). Thirty (59%) tumors were non-WNT/non-SHH. All indeterminate cases (except for 1 patient) had residual tumor. Hemostatic agents were found within the resection cavity in 80% of indeterminate cases. The most common sites of residual tumor were lateral (26/39, 67%, lateral recess and/or foramen of Luschka) and roof (25/39, 64%); the superior medullary velum was the most common region of the roof (19/25, 76%). Eight (16%) patients developed new neurological deficits: cranial nerve palsies in 5 patients and posterior fossa syndrome in 3 patients. Meticulous inspection of the resection cavity is necessary, paying particular attention to the roof and lateral recess. Hemostatic agents can conceal residual tumor.