A 62-year-old female presented with a rare massive parenchymatous metastasis from abdominal malignant lymphoma. Computed tomography and magnetic resonance image revealed a large enhanced mass in the right basal ganglia. 123I-IMP SPECT showed increased uptake on both early and delayed images. A stereotactic biopsy was performed; histological examination revealed a diffuse large B-cell malignant lymphoma. The patient underwent stereotactic radiosurgery (SRS). Short-term cliniconeuroradiological follow-up showed both neurologic improvement and virtually complete disappearance of the tumor. Our findings suggest that 123I-IMP SPECT can help differentiate malignant lymphoma from benign lesions and other malignant brain tumors. In addition, SRS with conventional radiotherapy may be an effective therapeutic strategy to control malignant lymphoma.