An update on the surgical treatment of malignant pineal region tumors

Our current pineal region tumor series (n = 34) now spans 11 years and currently includes 15 patients with malignant pineal region tumors, only 3 of whom had pure germinomas. Complete gross microsurgical excision of well-encapsulated tumors was possible in 9 of 13 patients (69%) who underwent definitive surgical exploration. Subtotal excision only was possible in 2 of the other patients. In the remaining 2 patients who had pineal germinomas, a less aggressive subtotal excision was done because of the known radiosensitivity of this tumor. Four of the operative patients had a tumor of mixed histology with benign and malignant components, emphasizing the need for adequate tissue sampling (Table 20.2). Eleven of the 13 surgical patients received postoperative craniospinal radiation; a 6-month-old girl who had a gross total excision of a pineoblastoma was too young to be irradiated. Ten of the patients continue to do well up to 12 years postoperatively. In view of the fact that only 3 of the 15 patients had pure germinomas, these results appear to be better than those reported with shunting and radiotherapy. Only one of our surgical patients developed postoperative metastases, an embryonal cell tumor that spread to the spinal canal. In the 34 patients in this series with lesions of the pineal region, surgical exploration was associated with only one death (a patient with metastatic adenocarcinoma). As is common with the occipital transtentorial approach, a postoperative hemanopsia is common but usually transient. The wide exposure of this approach, however, may be responsible for the greater proportion of complete gross excisions of malignant pineal tumors using other approaches (24). We have also shown the importance of tumor markers and that germinomas are very sensitive to chemotherapy. Thus, microsurgery for pineal tumors provides a viable potential for complete gross tumor extirpation even with malignant lesions, and/or adequate tissue for diagnosis which is necessary in appropriate therapeutic planning for radiotherapy and/or chemotherapy. The traditional therapeutic approach of empiric radiotherapy without a tissue diagnosis for pineal lesions may no longer be acceptable.