First Case Report of a Dog With Intracranial Granular Cell Tumor Treated With Stereotactic Radiotherapy

A 12-year-old male castrated Shih Tzu presented with a suspected intracranial granular cell tumor (GCT) in the left cerebrum. The clinical signs had resolved post stereotactic radiotherapy (SRT) of 3 consecutive days of 8 Gy, and serial magnetic resonance imaging (MRI) revealed maximum 56.8% tumor volume reduction 9 months post SRT. Serial MRI showed progressive cerebral microbleeds. The patient neurologically declined 18 months after SRT and was euthanized. A full necropsy, cytologic, and histologic analysis confirmed the diagnosis of GCT. This is the first reported canine case with cytologically and histologically confirmed intracranial GCT treated with SRT with serial MRI at regular intervals following treatment.