Non-islet-cell tumour hypoglycaemia in a cat with hepatocellular carcinoma

Abstract

Case summary An 11-year-old male neutered domestic shorthair cat presented with behavioural changes. Physical examination revealed bradycardia and a cranial abdominal mass. The cat was persistently hypoglycaemic (1.2 mmol/l; reference interval [RI] 3.5–5.5 mmol/l) with decreased fructosamine concentration suggesting chronic hypoglycaemia, and decreased insulin concentration excluding insulinoma. Alanine aminotransferase activity was markedly increased (1219.31 U/l; RI 15–60 U/l). On staging CT a large, multilobulated hepatic mass was identified, with no evidence of metastatic disease. After surgical removal serum glucose concentration and heart rate quickly returned to within the RIs. Histopathology was consistent with a solid-to-trabecular, well-differentiated, hepatocellular carcinoma. There was no recurrence of signs or mass during 8 months of follow-up, and the cat was still alive 20 months after surgery. Relevance and novel information Non-islet-cell tumour hypoglycaemia (NICTH) is a rare but life-threatening paraneoplastic syndrome. In humans, hepatocellular carcinoma is the most common epithelial tumour causing NICTH, but these are uncommon in cats, and associated paraneoplastic hypoglycaemia has not been reported. Possible mechanisms include aberrant secretion of big insulin growth factor 2; however, this could not be confirmed. NICTH should be considered in the differential diagnosis of cats with persistent hypoglycaemia.

Diagnosis of insulinoma in a Maine Coon cat

“…Non-islet cell tumors that produce factors with insulinomimetic effects are a rarely reported cause of feline hypoglycemia. 17 Other causes of hypoglycemia, such as exogenous insulin overdose and ingestion of sulfonylureas, must also be considered. Xylitol toxicity is an important differential for hypoglycemia in the dog that has not been reported in cats.…”

Juvenile hyperinsulinism in a Maine Coon kitten

“…Neoplasia was considered; however, non-insulinoma tumors producing hypoglycemia are generally associated with lower serum insulin levels. 5 – 7 While insulinoma could not be fully excluded based on ultrasound examination alone, 8 non-insulinoma neoplasia was further de-prioritized based on the normal ultrasound examination. 9 The necropsy findings of possible islet hyperplasia with no neoplastic beta cells ruled out insulinoma and was considered strongly suggestive of congenital hyperinsulinism.…”

Retrospective study of 20 cats surgically treated for insulinoma

“…A presumptive diagnosis can also be made by fulfilling the criteria of Whipple's triad, which includes the presence of clinical signs, serum blood glucose concentrations less than 60 mg/dl, and relief of clinical signs after feeding or glucose administration 1 . Differential diagnoses for pancreatic and extrapancreatic masses causing hypoglycemia in cats include INS, hepatoma, 11 acquired nisidioblastosis, 12 and hepatocellular carcinoma 13 …”

“…1 Differential diagnoses for pancreatic and extrapancreatic masses causing hypoglycemia in cats include INS, hepatoma, 11 acquired nisidioblastosis, 12 and hepatocellular carcinoma. 13 Surgical guidelines for the treatment of stage I INS (confined to the pancreas), stage II (lymph node metastasis) or stage III (distant metastasis) disease have not been established for cats and dogs. Nonsurgical perioperative management options include the use of dietary modifications, glucocorticoid administration, diazoxide, streptozocin, or octreotide in dogs.…”

“… 1 Differential diagnoses for pancreatic and extrapancreatic masses causing hypoglycemia in cats include INS, hepatoma, 11 acquired nisidioblastosis, 12 and hepatocellular carcinoma. 13 …”