Surgeons rehearsed on feline cadavers and used a custom 3D-printed template to remove the growth hormone-secreting mass in a 10-year-old cat. IGF-1 normalized within a week.
A 10-year-old cat from Hoboken, New Jersey, traveled to Bend, Oregon, for surgery to remove a growth hormone-secreting pituitary tumor that had left him with severe, insulin-resistant diabetes mellitus, the Veterinary Referral Center of Central Oregon (VRCCO) said.1
The cat, Mars, needed 20 units of insulin a day before the procedure, compared with a typical feline dose of 1 to 2 units. One week after surgery, his insulin-like growth factor 1 (IGF-1) concentration had returned to normal and his insulin requirement had dropped sharply, according to the practice.1
His internist in New York had kept increasing the dose, and that resistance led his doctors to suspect a pituitary tumor, which testing and an MRI confirmed, according to VRCCO.2
Mars had been diagnosed with hypersomatotropism, in which a pituitary tumor secretes excess growth hormone. “Left untreated, the excess growth hormone would continue to cause irreversible damage to Mars' heart, joints, and kidneys,” VRCCO said in a news release.1
The family considered continuing medical management or radiation to shrink the tumor, but VRCCO said neither option would have been a cure.2
The team performed a transsphenoidal hypophysectomy, reaching the pituitary gland through the soft palate. The gland sits at the base of the brain and is surrounded by major blood vessels. Using a custom 3D-printed surgical template and a 3D magnification camera system, the team worked through a 6 × 3-mm opening in the skull and removed the tumor in one piece, the practice said.1
The template was developed by VRCCO CEO Mauricio Dujowich, DACVS, according to the practice.1
Mars’ family searched nationwide for an experienced pituitary surgery team before finding VRCCO. His care team included Annie Chen-Allen, DACVIM (Neurology), along with Tina Owen, DACVS-SA, and Linda Martin, DACVECC, both of whom collaborated with Chen-Allen on pituitary surgeries during her tenure at Washington State University. VRCCO said the team has completed more than 30 pituitary surgeries together in dogs and cats.1
Before operating, Chen-Allen and VRCCO neurology intern Dani Madson practiced on feline cadavers to work out patient positioning, instrument placement, and how the surgical team would work together in the room, according to the practice.2
“This surgery has an incredibly high learning curve and a high mortality rate historically,” Chen-Allen said in the release. “Being able to successfully perform this micro-surgery requires an experienced team and an incredible orchestra of people.”1
In a 2021 retrospective study of 68 cats with hypersomatotropism and diabetes treated with transsphenoidal hypophysectomy at the Royal Veterinary College in the UK, 10 cats (15%) died within 4 weeks of surgery. Of all cats that underwent the procedure, 41 (60%) went into diabetic remission. The researchers concluded that the surgery is an effective treatment for these cats, with long-term outcomes that compare favorably with existing options.3
The tumor was small and firmly attached to Mars’ brain, which required slow dissection, according to VRCCO.2 In the ICU afterward, staff checked on him every 5 minutes, and the critical care team managed his electrolytes and hormones.1,2 He has since returned to New Jersey, where his neurological and physical strength continue to improve, the practice said.1
“He can finally jump again,” his owner said in the release. “After losing his ability to jump earlier this year and struggling to pull himself onto the couch, he just jumped all the way up onto our tall bar stool, it is a big win!”1
During her first visit after surgery, his owner tried their handshake trick, and Mars gave her a high five. “That’s when I knew,” she said. “My Mars is still my Mars.”2
VRCCO said Mars’ case illustrates the purpose of its medical travel program, which it expanded in July. Under the program, a specialty care coordinator gathers medical records, schedules appointments across departments, arranges same-day procedures or advanced diagnostics when possible, and shares travel and lodging resources. The practice also offers telehealth consultations before families travel and virtual follow-up appointments afterward.1,4
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