Supratentorial gangliogliomas: histopathologic grading and tumor recurrence in 184 patients with a median follow-up of 8 years.

Background: Supratentorial gangliogliomas (GGs) are rare tumors of the central nervous system and are commonly associated with chronic seizures. To date, only case reports and small series of patients with short-term follow-up have been available for the assessment of the potential of GGs to recur and progress.

Methods: Data from 184 patients who underwent resection of GGs between 1988 and 2001 were available from the University of Bonn Epilepsy Surgery Center (Bonn, Germany). Analysis of factors that influenced tumor recurrence and patient survival, such as preoperative history, age at operation, tumor location, histopathologic findings (including immunohistochemical findings), extent of tumor resection, and recurrence evaluated on postoperative magnetic resonance imaging (MRI), was performed.

Results: The median follow-up period was 8 years (range, 1-14 years). One hundred seventy-eight patients (97%) presented with long-term seizures (> or = 2 years). The median age at surgery was 26 years (range, 2-65 years). Tumor location was temporal in 79% of patients and frontal in 12% of patients. Eleven tumors (6%) were classified as World Health Organization (WHO) Grade 2 lesions, and 2 tumors were classified as anaplastic WHO Grade 3 lesions. For 38 patients (21%), postoperative MRIs revealed residual tumors. Two years after surgery, 5 patients (3%) experienced tumor recurrence, which resulted in malignant progression in 3 patients (2%) and death in 2 patients (1%). Eighty-four percent of patients with epilepsy had complete and sustained seizure relief. The calculated 7.5-year recurrence-free survival rate was 97%. Lower rates of recurrence were found in patients with tumors classified as WHO Grade 1 lesions (P < 0.0001), patients with temporal lesions (P < 0.0001), patients who underwent complete tumor resection (P = 0.0278), and patients with long-standing epilepsy (P < 0.0001).

Conclusions: Supratentorial GGs are benign tumors, and the surgical goal for patients with GG should be complete resection. Residual tumor masses, frontal tumor location, and WHO Grade 2 or 3 lesions are associated with a greater risk of recurrence or malignant progression. Patients with such characteristics should be considered for long-term clinical follow-up using MRI. .