Chemoreceptor Organ Pathology Flashcards
What is the function of chemoreceptor cells?
Measure the blood pH and oxygen and can send signals to the rest of the body
What is the function of stellate cells?
Keep everything together/ attach everything
What are the two main locations of paraganglia?
Carotid bodies and aortic bodies
What are the two names for chemodectomas?
aortic and carotid body tumours
What is the paraganglia?
- Non-Chromaffin, extra-adrenal cells
- Act as Chemoreceptors (parenchymal cells)
- Can also be stellate/ Sustentacular cells (stroma that attaches everything together)
Where are neoplasms of the aortic body most commonly seen?
at the base of the heart
What type of neoplasm is an aortic body neoplasm?
they are most commonly benign instead of malignant
adenoma instead of carcinoma
What are the main dog breeds that are affected by aortic body neoplasms?
brachycephalic breeds
What is the problem with aortic body neoplasms being space occupying?
they can inavde blood vessels/ compress the heart and cause a functional disturbance
cardiac decompensation
What may a carotid body adenoma look like grossly?
- Small, less than 4cm
- Encapsulated
- Carotid = incorporated
- Smooth, firm, white
- Highly vascularised
What may a carotid body carcinoma look like?
- Large
- Irregular and Multinodual
- Carotid artery and jugular veins may also be incorporated
What is an ectopic thyroid tumour a differential for?
aortic body tumour
What percentage of heart based tumours do ectopic thyroid tumours make up?
5-10%
What part of the body do ectopic thyroid tumours invade?
inavde structures in the cranial mediastinum
Where can chemoreceptors be found?
- Nodose ganglion in the vagus nerve
- pancreas
- cilliary ganglion
- internal jugular vein
- glossopharyngeal nerve
What are the histological signs of chemoreceptor malignancy?
- Anisocytosis/ anysokaryosis
- Vascular invasion
- Necrosis
What is a chemodectoma?
tumour which arises from specialised cells which are found in particular blood vessels including the aorta, before it leaves the heart
What does a chemodectoma look like grossly?
- attached to the adventitia of aorta/pulmonary artery
- found within adipose connective tissue
- firm smooth masses (white to tan)
Where is a carotid body neoplasm usually found?
Near the bifurcation of the common carotid artery (cervical area)
also commonly found in brachycephalic breeds
What does an ectopic thyroid tumour invade?
Invades structures in teh cranial mediastinum
What cell types are found in ectopic thyroid tumours
- Smaller cells
- hyperchromastic nuclei and eosinophillic cytoplasm
- primitive follicular structures or colloid containing follicles
- thyroglobulin- TTF-1 IHC
Name 4 predisposoutions to chemoreceptor tumours
- Genetics
- Brachycephalic dogs
- Hypoxia
- Humans living at higher altitudes
