Diagnosis of insulinoma in a Maine Coon cat

Abstract

Case summary A 9-year-old male neutered Maine Coon cat presented with a 6-month history of polyphagia and one recent episode of tremors and weakness. Blood work revealed profound hypoglycemia and results of a paired insulin glucose test were consistent with an insulinoma. Abdominal ultrasound revealed a solitary pancreatic mass, and results of a fine-needle aspirate (FNA) gave further support for the location of the neuroendocrine tumor. After unsuccessful medical management of the hypoglycemia, the mass was surgically removed. Immunohistochemistry confirmed that it was an insulinoma. At the time of writing, the patient had been in clinical remission for 9 months. Relevance and novel information Feline insulinomas are rare and there is very little information on their behavior, clinical course and histologic characteristics. This is the first reported case of an insulinoma in a Maine Coon cat and the first to describe results of an ultrasound-guided FNA of the mass. In addition, the progression of disease, histopathology and immunohistochemistry results add to the currently minimal database for feline insulinomas.

Intrapancreatic accessory spleen mimicking pancreatic insulinoma with intrapancreatic metastasis in a cat

“…Ultrasonographic echogenicity of canine insulinomas have been reported as hypoechoic [ 20 , 24 , 31 ]. However, that of the mass in this case was isoechoic, which was inconsistent with previous feline cases [ 4 , 11 , 33 , 34 ]. Variations of echogenicity might also contribute to the reduced detection sensitivity of abdominal ultrasonography in feline insulinomas.…”

“…Pancreatic insulinomas are functional beta cell tumors that cause persistent hypoglycemia because of inappropriate insulin secretion. Although there are various reports of canine pancreatic insulinomas [ 3 , 17 , 21 , 23 ], the tumors are extremely rare in cats, with only nine well-documented cases in the literature [ 4 , 11 , 12 , 13 , 16 , 25 , 27 , 33 , 34 ]. Diagnostic imaging modalities for canine pancreatic insulinomas reported previously include ultrasonography [ 20 , 28 , 31 , 37 ], contrast-enhanced ultrasonography [ 26 , 39 ], computed tomography (CT) [ 2 , 6 , 8 , 14 , 24 , 31 ], single-photon emission CT (SPECT) [ 31 , 32 ] and somatostatin receptor scintigraphy [ 10 , 22 ].…”

Retrospective study of 20 cats surgically treated for insulinoma

“…Two previous cases of stage III feline INS have been documented; however, 1 cat had no follow up 17 and the other was euthanized on presentation with final diagnosis made on postmortem examination 19 . All of the previous case reports were cats with stage I disease 2–9 . Similar findings were noted in 2 larger canine studies in which pathologic stage was a predictor of survival time 10,22 .…”

“…Surgical complications reported for INS include seizures, pancreatitis, ongoing hypoglycemia, transient hyperglycemia, and death 2–9 . In our study, the complication and mortality rates were 25% and 10%, respectively, with 90% of cats surviving to hospital discharge.…”

“…Cat 18 had a left‐sided mass and was euthanized 5 days postoperatively; Cat 19 had a midbody mass and survived to discharge. Other complications reported in canines include diabetes mellitus and endocrine pancreatic insufficiency 9 . Eighteen out of 20 (90%) of cats were euglycemic or hyperglycemic postoperatively.…”