Pancreatic Glucagonoma

Clinical Features

glucagonoma is a rare endocrine tumor of the α pancreatic cells and has been reported in 8 dogs
Glucagonoma is associated with a characteristic dermatitis of the footpads = superficial necrolytic dermatitis
Synonyms: metabolic epidermal necrosis, necrolytic migratory erythema, and diabetic dermatitis
Skin lesions can also occur on the muzzle, mucocutaneous junctions, elbow, hocks, pinnae, and external genitalia
Skin lesions tend to wax and wane and can be pruritic with secondary bacterial infections
However, superficial necrolytic dermatitis is not pathognomonic for glucagonoma as 78 cases of superficial necrolytic dermatitis have been reported and only 7 of these were diagnosed with concurrent glucagonoma
Classification scheme has been proposed: superficial necrolytic dermatitis, superficial necrolytic dermatitis and hepatocutaneous syndrome, and suspected superficial necrolytic dermatitis, with glucagonoma reported in:
9% of dogs with superficial necrolytic dermatitis
60% of dogs with superficial necrolytic dermatitis and hepatocutaneous syndrome
31% of dogs with suspected superficial necrolytic dermatitis
Superficial necrolytic dermatitis resolves following successful surgical resection of the pancreatic glucagonoma
DDx: pemphigus foliaceus, SLE, generic dog food dermatosis, and zinc-responsive dermatosis

alt text

From: Withrow SJ & MacEwen EG (eds): Small Animal Clinical Oncology (3rd ed).

Glucagon promotes gluconeogenesis and glycogenolysis
Hyperglycemia will result if there is an excess of glucagon relative to insulin
Diabetes mellitus will occur if insulin production cannot match the excessive secretion of glucagon

Other clinical signs include weight loss, polyuria, and polydipsia
Weight loss is caused by the catabolic effects of glucagon on fat and protein metabolism

Hematologic and serum biochemical abnormalities include non-regenerative anemia and elevated liver enzymes ± hypoalbuminemia, decreased BUN, and persistent hyperglycemia
Skin biopsy: diffuse parakeratotic hyperkeratosis with high levels of confluent vacuolation of keratinocytes resulting in epidermal edema, with minimal dermal changes (i.e., perivascular accumulation of lymphocytes and plasma cells)
Chronic lesions may have superficial to lichenoid inflammatory infiltrates
Abdominal and thoracic imaging for detection of a pancreatic mass and metastatic disease
However, pancreatic mass was only detected in 13% (1/8) dogs with ultrasonographic examination
Multiple diffuse hypoechogenic foci in the liver (= honeycomb pattern) is present in 50% (4/8) dogs with glucagonoma and is consistent with hepatic metastases
Plasma glucagon levels in the absence of hypoglycemia strongly supports the diagnosis of glucagonoma

Exploratory celiotomy with partial pancreatectomy and clinical staging for metastatic disease
Tumor debulking can decrease the intensity of skin lesions in humans with glucagonoma
Octreotide is recommended for medical management of humans with glucagonoma
Other medical treatment options include decarbazine and streptozotocin with 5-fluoroucil