Chemoreceptor Organ Pathology

Question 1

What is the function of chemoreceptor cells?

Answer 1

Measure the blood pH and oxygen and can send signals to the rest of the body

Question 2

What is the function of stellate cells?

Answer 2

Keep everything together/ attach everything

Question 3

What are the two main locations of paraganglia?

Answer 3

Carotid bodies and aortic bodies

Question 4

What are the two names for chemodectomas?

Answer 4

aortic and carotid body tumours

Question 5

What is the paraganglia?

Answer 5

• Non-Chromaffin, extra-adrenal cells
• Act as Chemoreceptors (parenchymal cells)
• Can also be stellate/ Sustentacular cells (stroma that attaches everything together)

Question 6

Where are neoplasms of the aortic body most commonly seen?

Answer 6

at the base of the heart

Question 7

What type of neoplasm is an aortic body neoplasm?

Answer 7

they are most commonly benign instead of malignant

adenoma instead of carcinoma

Question 8

What are the main dog breeds that are affected by aortic body neoplasms?

Answer 8

brachycephalic breeds

Question 9

What is the problem with aortic body neoplasms being space occupying?

Answer 9

they can inavde blood vessels/ compress the heart and cause a functional disturbance

cardiac decompensation

Question 10

What may a carotid body adenoma look like grossly?

Answer 10

• Small, less than 4cm
• Encapsulated
• Carotid = incorporated
• Smooth, firm, white
• Highly vascularised

Question 11

What may a carotid body carcinoma look like?

Answer 11

• Large
• Irregular and Multinodual
• Carotid artery and jugular veins may also be incorporated

Question 12

What is an ectopic thyroid tumour a differential for?

Answer 12

aortic body tumour

Question 13

What percentage of heart based tumours do ectopic thyroid tumours make up?

Answer 13

5-10%

Question 14

What part of the body do ectopic thyroid tumours invade?

Answer 14

inavde structures in the cranial mediastinum

Question 15

Where can chemoreceptors be found?

Answer 15

• Nodose ganglion in the vagus nerve
• pancreas
• cilliary ganglion
• internal jugular vein
• glossopharyngeal nerve

Question 16

What are the histological signs of chemoreceptor malignancy?

Answer 16

• Anisocytosis/ anysokaryosis
• Vascular invasion
• Necrosis

Question 17

What is a chemodectoma?

Answer 17

tumour which arises from specialised cells which are found in particular blood vessels including the aorta, before it leaves the heart

Question 18

What does a chemodectoma look like grossly?

Answer 18

• attached to the adventitia of aorta/pulmonary artery
• found within adipose connective tissue
• firm smooth masses (white to tan)

Question 19

Where is a carotid body neoplasm usually found?

Answer 19

Near the bifurcation of the common carotid artery (cervical area)
also commonly found in brachycephalic breeds

Question 20

What does an ectopic thyroid tumour invade?

Answer 20

Invades structures in teh cranial mediastinum

Question 21

What cell types are found in ectopic thyroid tumours

Answer 21

• Smaller cells
• hyperchromastic nuclei and eosinophillic cytoplasm
• primitive follicular structures or colloid containing follicles
• thyroglobulin- TTF-1 IHC

Question 22

Name 4 predisposoutions to chemoreceptor tumours

Answer 22

• Genetics
• Brachycephalic dogs
• Hypoxia
• Humans living at higher altitudes