ISSN 2398-2950      

Pheochromocytomas

ffelis
Contributor(s):

Sarah Gould

Synonym(s): Phaeochromocytoma


Introduction

  • Very rare tumors (only 3 reported cases).
  • Usually unilateral, slow growing adrenal masses.
  • Occasionally extra-adrenal.
  • May reach a considerable size before clinical signs.
  • Signs: often vague - intermittent tachycardia, hypertension.
  • Diagnosis: histopathology, hormonal assay.
  • Treatment: surgery.
  • Prognosis: guarded.

Pathogenesis

Predisposing factors

General

  • Chromaffin cell adrenal tumor or may be derived from extra-adrenal paraganglionic tissue.
  • Secrete catecholamines (80% noradrenaline) which   →   vasoconstriction and hypertension by action on alpha and beta receptors   →   signs.
  • Release often intermittent (may be mediated by changes in tumor blood flow and trauma   →   intermittent signs.
  • May be malignant; if so, may invade caudal vena cava or metastasize to lung, liver or bone
  • Occasional incidental post mortem finding.

Pathophysiology

  • Signs related to release of catecholamines.
  • Secretion of catecholamines is often intermittent and so signs are correspondingly variable and range from subclinical to cardiovascular collapse.
  • Signs are related to secretion of catecholamines and their systemic effects:
    • Generalized vasoconstriction by stimulation of alpha receptors.
    • Positive chronotropic and inotropic effects on the heart.
    • Capillary dilation and reduced gastrointestinal motility caused by stimulation of beta2 receptors.

Timecourse

  • Weeks to years.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Daniel G, Mahony O M, Markovich J E et al (2015) Clinical findings, diagnostic and outcome in 33 cats with adrenal neoplasia (2002-2013). J Feline Med Surg 18 (2), 77-84 PubMed
  • Chun R, Jakovijevic S, Morrison W B et al (1998) Apocrine gland adenocarcinoma and pheochromocytoma in a cat. JAAHA 33 (1), 33-36 PubMed.
  • Maher E R Jr. (1994) Pheochromocytoma in the dog and cat - diagnosis and management. Sem Vet Surg (Small Animal) (3), 158-166 PubMed.
  • Henry C J, Brewer W G Jr., Montgomery R D et al (1993) Clinical vignette.​ Adrenal Pheochromocytoma. JVIM (3), 199-201 PubMed.
  • Patnaik A K, Erlandson R A, Lieberman P H et al (1990) Extra-adrenal pheochromocytoma (paraganglioma) in a cat. JAVMA 197 (1), 104-106 PubMed.

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