Neoplasms involving the central nervous system in the older old.

Geriatric cancer patients present special challenges for clinicians. Few large series have been published in the last 20 years on the types of neoplasms that involve the central nervous system (CNS) in older individuals. To review types of neoplasms involving the central CNS that are currently being encountered by pathologists and neurosurgeons, we identified from our databases for the years 1992-2002, inclusive, patients 75 years or older who had symptomatic lesions requiring neurosurgical interventions. Retrospective characterization of tumors by immunohistochemistry, in situ hybridization, and fluorescence in situ hybridization was performed whenever possible and relevant to tumor type. Neurosurgical procedures (n=125) on 119 patients were identified; 90 patients were diagnosed as having neoplasms, with clot evacuation or infections being the most frequent non-neoplastic conditions necessitating surgery. Tumor types included glioblastomas (36 patients), meningiomas (16), pituitary adenomas (12), lymphomas or other hematological malignancies (8), anaplastic gliomas (5), metastases (6), head and neck malignancies with direct intracranial extension (3), and other miscellaneous tumor types (4). Compared with older literature series, we encountered a larger number of elderly patients with CNS lymphomas and fewer who came to surgery for CNS metastatic disease. In the "older old", glioblastomas are the most frequent symptomatic tumors necessitating surgical intervention. Glioblastomas in this aged cohort display the signature features of the small cell phenotype (62%), high cell cycle labeling indices (mean MIB-1-labeling index=25.1%), and either amplification of epidermal growth factor receptor or gain of chromosome 7 by fluorescence in situ hybridization (93% of assessable cases).