MR OF RECURRENT HIGH-GRADE ASTROCYTOMAS AFTER INTRALESIONAL IMMUNOTHERAPY

PURPOSE: To describe the MR findings in six patients with recurrent ce rebral astrocytomas before, immediately after, and 3 months after loca l immunotherapy with tumor-infiltrating lymphocytes and interleukin-2. METHODS: Contrast-enhanced MR studies were obtained in six patients ( three with anaplastic astrocytoma and three with glioblastoma multifor me) at the time of tumor recurrence, after a second resection and plac ement of an Ommaya catheter, at the end of immunotherapy, and thereaft er at 3-month intervals. These MR studies were reviewed with special a ttention to pattern and degree of enhancement, edema, and mass effect. RESULTS: In three patients, gross total removal of recurrent tumor wa s achieved and postimmunotherapy MR studies showed a flare phenomenon characterized by increased nodular enhancement, increased edema, and m ass effect. On the 3-month follow-up examination, these findings had r esolved, and no further tumor recurrence was seen during the following 12-month period. Neither of the two patients who had subtotal resecti on had a Bare phenomenon. In one of these patients, the tumor was stab le at the 12-month follow-up; the other patient had recurrent tumor at the 6-month follow-up, In the last patient, who also had subtotal tum or resection and progressive enhancement after immunotherapy, tumor pr ogression was rapid. CONCLUSION: After local immunotherapy, increased enhancement, edema, and mass effect are most likely the result of a fl are phenomenon, but because rapid tumor progression may produce simila r features, follow-up MR studies are indispensable. The flare phenomen on resolved by 3 months in all patients.