ISSN 2398-2950      

Pituitary gland: neoplasia


Synonym(s): Pituitary adenoma, pituitary macroadenoma


  • Intracranial neoplasms are rare in cats (3.5/100,000), and pituitary tumors are the third most common intracranial neoplasm, making up less than 10% of such neoplasms, with meningioma Meningioma  most common and lymphoma Lymphoma second most common. 
  • Pituitary tumors in cats are more likely to be functional than similar tumors in dogs, and presenting signs may relate to endocrine disease. The most common pituitary tumor is the somatotroph adenoma, which can cause hypersomatotropism/acromegaly, and the second-most common is the corticotroph adenoma. 
  • Hypersomatotropism is increasingly recognized, with prevalence rates of 18% to 32% in cats with diabetes mellitus (DM). 
  • 80-85% of feline hyperadrenocorticism is the result of pituitary disease. 
  • Hypersomatotropism refers to a condition of excessive growth hormone, acromegaly refers to the constellation of associated signs. 



  • No known specific carcinogenic risk factors spontaneous neoplasia.
  • Speculation on whether organohalogenated chemicals (OHCs) play a role in the formation of somatotroph adenoma.  
  • The aryl-hydrocarbon-receptorinteracting protein (AIP) gene was found to have a single nonsynonymous single-nucleotide polymorphism (SNP) in 20% of studied cats with acromegaly.


  • If acromegaly Acromegaly is present, it is usually due to a functional adenoma of the pars distalis adenohypophysis.
  • Pituitary tumors may be functional, with signs arising from both space-occupying lesion effects, and effects due to tumor products, OR tumor may be non-functional, with effects arising primarily from the space-occupying lesion.
  • Functional chromophobe (corticotroph) adenomas of pars distalis may secrete excess ACTH autonomously, causing hyperadrenocorticism Hyperadrenocorticism.
  • Non-functional chromophobe adenomas reported also, with signs related to local extension and compression of optic nerves and other structures.
  • Functional acidophil adenomas of par distalis secrete excess growth hormone (x30-x100 normal serum levels), with associated acromegaly Acromegaly and insulin-resistant diabetes mellitus Diabetes mellitus.
  • Tumors may arise from pars intermedia also, with associated raised serum alpha-MSH (melanocyte stimulating hormone).


  • Timecourse reflects neoplastic growth (space-occupying effects) and/or function (hormonal effects), over weeks to months.


  • Typically isolated, spontaneous neoplasms.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Cook A K, Evans J B (2021) Feline comorbidities: Recognition, diagnosis and management of the cushingoid diabetic. J Feline Med Surg 23(1), 4-16 PubMed.  
  • Fenn J, Kenny P J, Scudder C J, Hazuchova K, Gostelow R et al (2021) Efficacy of hypophysectomy for the treatment of hypersomatotropism-induced diabetes mellitus in 68 cats. J Vet Intern Med DOI: 10.1111/jvim.16080​ PubMed.
  • Miller M A, Piotrowski S L, Donovan T A, Scott-Moncrieff J C, Owen T J et al (2021) Feline Pituitary Adenomas: Correlation of Histologic and Immunohistochemical Characteristics With Clinical Findings and Case Outcome. Vet Pathol 58(2), 266-275 PubMed.  
  • Nastri Gouvêa F, Santos Pennacchi C, Doutel Assaf N, de Oliveira Branco L, Barbosa Costa P, Alves Dos Reis P, Borin-Crivellenti S (2021) Acromegaly in dogs and cats. Ann Endocrinol (Paris) DOI: 10.1016/j.ando.2021.03.002​ PubMed.
  • Sanders K, Galac S, Meij B P (2021) Pituitary tumour types in dogs and cats. Vet J 270, 105623 PubMed.  
  • van Bokhorst K L, Galac S, Kooistra H S, Valtolina C, Fracassi F, Rosenberg D, Meij B P (2021) Evaluation of hypophysectomy for treatment of hypersomatotropism in 25 cats. J Vet Intern Med DOI: 10.1111/jvim.16047​ PubMed.
  • Fleeman L, Gostelow R (2020) Updates in Feline Diabetes Mellitus and Hypersomatotropism. Vet Clin North Am Small Anim Pract 50(5), 1085-1105 PubMed
  • Körner M, Roos M, Meier VS, Soukup A, Cancedda S, Parys M M et al (2019) Radiation therapy for intracranial tumours in cats with neurological signs. J Feline Med Surg 21(8),765-771 PubMed.
  • Sawada H, Mori A, Michishita M, Oda H, Sako T (2019) Long-term management and postmortem examination in a diabetic cat with acromegaly treated with two courses of radiation therapy. J Vet Med Sci 81(1), 71-76 PubMed.  
  • Wormhoudt T L, Boss M K, Lunn K, Griffin L, Leary D, Dowers K et al (2018) Stereotactic radiation therapy for the treatment of functional pituitary adenomas associated with feline acromegaly. J Vet Intern Med 32(4), 1383-1391 PubMed.  
  • Gostelow R, Scudder C, Keyte S, Forcada Y, Fowkes R C et al (2017) Pasireotide Long-Acting Release Treatment for Diabetic Cats with Underlying Hypersomatotropism. J Vet Intern Med 31(2), 355-364 PubMed.  
  • Scudder C J, Niessen S J, Catchpole B, Fowkes R C, Church D B, Forcada Y (2017) Feline hypersomatotropism and acromegaly tumorigenesis: a potential role for the AIP gene. Domest Anim Endocrinol 59, 134-139 PubMed
  • Fletcher J M, Scudder C J, Kiupel M , Pipe-Martin H N, Kenny P J et al (2016) Hypersomatotropism in 3 Cats without Concurrent Diabetes Mellitus. J Vet Intern Med 30(4), 1216-1221 PubMed
  • Fischetti A J, Gisselman K, Peterson M E (2012) CT and MRI evaluation of skull bones and soft tissues in six cats with presumed acromegaly versus 12 unaffected cats. Vet Radiol Ultrasound 53(5), 535-539 PubMed.
  • Brearley M J & Polton G A (2005) Coarse fractionated radiation therapy for pituitary tumors in cats: a retrospective study of 10 cases. Vet Comp Oncol (1), 38-39 Wiley Online Library.
  • Meij B P, van der Vlugt-Meijer R H, van den Ingh T S et al (2004) Somatotroph and corticotroph pituitary adenoma (double adenoma) in a cat with diabetes mellitus and hyperadrenocorticism. J Comp Pathol 130 (2-3), 209-215 PubMed.
  • Neiger R, Witt A L, Noble A et al (2004) Trilostane therapy for treatment of pituitary-dependant hyperadrenocorticism in 5 cats. J Vet Intern Med 18 (2), 160-164 PubMed.
  • Troxel M T, Vite C H, Massicotte C et al (2004) Magnetic resonance imaging features of feline intracranial neoplasia: retrospective analysis of 46 cats. J Vet Intern Med 18 (2), 176-189 PubMed.
  • Skelly B J, Petrus D, & Nicholls P K (2003) Use of trilostane for the treatment of pituitary-dependant hyperadernocorticism in a cat. J Small Anim Pract 44 (6), 269-272 PubMed.
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  • Kaser-Hotz B, Rohrer C R, Stankeova S et al (2002) Radiotherapy of pituitary tumours in five cats. J Small Anim Pract 43 (7), 303-307 PubMed.
  • Meij B P, Voorhout G, Van Den Ingh T S et al (2001) Transsphenoidal hypophysectomy for treatment of pituitary-dependent hyperadrenocorticism in 7 cats. Vet Surg 30 (1), 72-86 PubMed.
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  • Zaki F A & Liu S K (1973) Pituitary chromophobe adenoma in a cat. Vet Pathol 10 (3), 232-237 PubMed.

Other sources of information

  • Lunn K L, Boston S E (2020) Tumors of the endocrine system. In: Small Animal Clinical Oncology. 6th edn. Eds Withrow&MacEwen’s. Elsevier Saunders, St. Louis. pp 565-570. 
  • Capen C C (2002) Tumors of the Endocrine Glands. In: Meuten D J (ed)Tumors in Domestic Animals. 4th edn. Ch 13 pp 607-696. Iowa State Press.

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