1.4 Pancreas Pathology and Chemoreceptors

Describe normal pancreas anatomy (or just read)

islets of langerhans (endocrine tissue) is scattered throughout exocrine tissue

exocrine cells have bright eosinophilic zymogen granules, islet cells have moderate amounts of pale eosinophilic to amphophilic cytoplasm

islets are composed of multiple populations of cells indistinguishable without special stains

islet hyperplasia is most common in what species? (2)

dogs

horses

T/F islet hyperplasia is rarely appreciated in domestic animals and is probably underdiagnosed

true

islet hyperplasia is a ________ process following injury with partial loss (could be surgery) of islets or with decreased synthetic function of islets or antagonism of their hormone products

compensatory

what species are islet cell tumors, insulinomas specifically, most common in? (3)

dogs

cattle

ferrets

what cells does islet cell tumors typically originate from?

what are these tumors called when they originate from these cells?

are these tumors typically functional or nonfunctional?

beta cells

insulinoma

functional

Are islet cell adenomas or carcinomas more common in dogs?

carcinomas

Describe gross appearance of islet cell adenomas

usually solitary, well-circumscribed

T/F islet cell carcinomas are more invasive and then to be larger than adenomas

true

T/F islet cell carcinomas can met early when primary is still small (

True

what species are the less common gastrinoma islet cell tumors most common in?

dogs

cats

where are gastrinomas derived from?

Diffuse neuroendocrine system or multipotent stem cells

T/F excess gastrin = gastric acid hypersecretion

true

what are associated pathologies with gastrinomas? (2)

gastric ulceration

vomiting

what species are the less common glucagonoma islet cell tumors most common in?

dogs

what are associated pathologies for glucagonoma? (3)

Superficial necrolytic dermatitis

diabetes mellitus

vacuolar hepatopathy

what causes superficial necrolytic dermatitis associated with glucagonoma?

hypoaminoacidemia

why do patients with glucagonoma become diabetic?

glucagon increases gluconeogenesis, outpaces insulin levels

__________ ___________ __________: erythema, hyperkeratotic crusting, erosion of footpads, mucocutaneous junctions, ears frictional pressure points associated with glucagonoma

superficial necrolytic dermatitis

with glucagonoma, excess glucagon leads to what?

insulin-antagonistic effects due to hepatic gluconeogenesis and glycogenolysis diabetes

What characterisitc pattern on histology is associated with glucagonomas?

french flag pattern (edema in epidermis, proliferation basal cells)

what pancreas pathology is seen in type 2 diabetic cats and to a lesser extent in some older non diabetic cats and is characterized by replacement of islets by homogenous, amorphous, extracellular aggregates of eosinophilic material?

islet amyloidosis

what species is islet amyloidosis most commonly seen in?

cats

T/F islet amyloidosis is part of systemic amyloidosis, so you should expect to find amyloid in the rest of the body if it is found in the pancreas

False; it is localized

what species is islet vacuolar degeneration most commonly seen in? (2)

dogs

cats

islet vacuolar degeneration is seen in cats with what condition?

chronic type II diabetes

what would you see on histology for islet vacuolar degeneration?

Islet cells are reduced in number and vacuolated (glycogen)

what causes islet vacuolar degeneration?

long-term overstimulation and exhaustion due to peripheral insulin resistance

what species is pancreatic necrosis with destruction of islets and resultant type 1 diabetes most commonly seen in? (2)

dogs

cattle

pancreatic necrosis is related to what condition in dogs?

acute necrotizing

pancreatitis

pancreatic necrosis is related to what two conditions in cattle? (2)

BVDV (pestivirus)

foot and mouth disease virus (picronavirus)

Now onto chemoreceptors

chill

what structures sense blood O2 and CO2 and have afferent nerve fibers that go to the brainstem to help regulate breathing rate?

chemoreceptors

what two cell types compose chemoreceptors?

type 1 (glomus) cells

type 2 (glial) cells

T/F type 1 chemoreceptor cells have autocrine and paracrine signaling but no endocrine signaling

true

what species are aortic body tumors, carotid body tumors (chemodectomas) most commonly seen in?

dogs

describe gross appearance of aortic body tumors and carotid body tumors

single masses or multiple nodules within the pericardial sac near the base of the heart ("heart base tumors")

what types of dogs and cattle are more predisposed to aortic body and carotid body tumors?

brachycephalic dogs

cattle at high altitudes

where can dispersed neuroendocrine system tumors be located?

throughout the respiratory, GI, and genital tract, including the liver and pancreas (carcinoids)

what can dispersed neuroendocrine system tumors secrete if they are functional?

vasoactive amines and gastrin