Second-look surgery for pineal region tumors

Purpose: Surgical resection of pineal region tumors is challenging because of close proximity to the vein of Galen draining system and the quadrigeminal plate. Surgical resection usually is performed through the narrow corridor by piecemeal resection and en bloc resection is difficult in cases of large tumors. Moreover, in cases of hypervascular tumors, surgical resection through the narrow corridor could entail massive intraoperative bleeding. The effectiveness of neoadjuvant chemotherapy and second-look surgery for pineal region tumors for maximal safe resection was evaluated.

Methods: Retrospective institutional review of pediatric patients with pineal region tumors who underwent second look surgery after neoadjuvant chemotherapy was performed.

Results: Nine patients underwent surgical resection after neoadjuvant chemotherapy over the period of September 2017 to February 2022. The mean age was 7.7 years (ranged from 1.4 to 15.3 years). Three patients underwent partial resection via open craniotomy, and 6 underwent endoscopic biopsy as an initial surgery. The histopathological diagnoses were germ cell tumors in 5 patients (yolk sac tumors in 2, germinoma in 2, choriocarcinoma in 1), /rhabdoid tumor (AT/RT) in 2, medulloblastoma in 1, and high-grade glioneuronal tumor in 1. After several courses of chemotherapy, the second-look surgery was performed. The tumor volume was reduced in 8 patients (89%) after chemotherapy except for 1 case of growing teratoma syndrome. The tumor was extended laterally to the ambient cistern in 2 patients, and posteriorly to the tentorial surface of the cerebellum in 3 patients. The lesion was approached through occipital transtentorial approach in 8 patients and infratentorial supracerebellar approach in 1. Intraoperatively, the high vascularity of the tumor was not observed in all cases. Gross total resection (8 patients, 89%) or near total resection (1, 11%) was achieved in all cases. No complications were observed postoperatively in all cases. Eight patients subsequently underwent additional chemo-radiation therapy according to the initial diagnosis. All patients are alive with no evidence of recurrence with a mean follow-up of 33 months.

Conclusions: Neoadjuvant chemotherapy and second-look surgery for pediatric pineal region tumors was considered to be effective in reducing the tumor volume and vascularity, which facilitates the safe maximal tumor resection.