Suspected olfactory meningioma and synchronous pituitary microadenoma in a canine patient treated with radiation therapy

The authors report on the rare occurrence of dual synchronous primary brain tumors in a canine patient, successful treatment with radiation therapy, and medical therapy with patient stabilization for almost three years. A 12.5-year-old spayed mixed-breed female Labrador was referred to Purdue Veterinary Hospital to treat hyperadrenocorticism of suspected pituitary origin. During MRI imaging, the presence of two possible brain neoplasms was detected: a possible right olfactory bulb meningioma and a microadenoma of the pituitary gland. The patient was treated with a fractionated course of radiation in both tumors, 15 treatments of 3Gy, which limited the tumor growth. Mitotane therapy corrected the hormonal dysregulation. The dog had a normal life for nearly three years and recently passed. Cancer cells were not found at necropsy. No MEN1 germline mutations were identified in constitutional DNA (from blood) via high-coverage whole genome sequencing.