Canis ISSN: 2398-2942

Brain: neoplasia - choroid plexus tumor

Synonym(s): Choroid plexus carcinoma; Choroid plexus papilloma

Contributor(s): Laurent Garosi, Simon Platt


  • Account for approximately 10% of all primary intracranial central nervous system tumors.
  • Signs: depending on location of the tumour can cause focal forebrain signs or focal cerebello-medullary signs - occasionally diffuse forebrain signs if causes secondary obstructive hydrocephalus.
  • Diagnosis: signs, MRI, definitive diagnosis only by biopsy (often post-mortem).
  • Treatment: palliative medical treatment, palliative ventriculo-peritoneal shunting (if associated with obstructive hydrocephalus), surgical resection, radiotherapy.
  • Prognosis: tend to invade the ventricular system, can cause drop metastasis in the cerebrospinal fluid (CSF) system.



  • Arise from the choroid plexus of the lateral, third or fourth ventricles.
  • Most commonly arise in the fourth ventricle.
  • Less often in the choroid plexuses of the lateral and third ventricles.

Predisposing factors

  • Presently unknown.


  • Presently unknown.


  • Over 50% of choroid plexus tumors are reported to arise from the fourth ventricle with the rest occurring equally in third and lateral ventricles.
  • Choroid plexus cells arise from a primitive medullary epithelium and are related to ependymal cells.
  • Choroid plexus tumors may be either papillomas, which are more common, or carcinomas.
  • Choroid plexus carcinomas are rare compared to their more benign counterpart. They have historically been distinguished from papillomas by their cellular anaplasia, high mitotic rate, invasiveness, and metastatic implantation.
  • Local microscopic spread within the ventricular system can occur with choroid plexus papilloma and distant metastases to the subarachnoid space occur in up to half of the dog with choroid plexus carcinoma.
  • Because of their ventricular orientation choroid plexus tumor have a tendency to obstruct cerebrospinal pathways, particularly when they arise in the fourth or third ventricles. The result is obstructive hydrocephalus.


  • Insidious onset and progressive.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Westworth D R, Dickinson P J, Vernau W et al (2008) Choroid plexus tumors in 56 dogs (1985-2007). J Vet Intern Med 22, 1157-1165 PubMed.
  • Snyder J M, Shofer F S, Van Winkle T J et al (2006) Canine intracranial primary neoplasia: 173 cases (1986-2003). J Vet Intern Med 20, 669-675 PubMed.
  • Lipsitz D, Levitski R E, Chauvet A E (1999) Magnetic resonance imaging of a choroid plexus carcinoma and meningeal carcinomatosis in a dog. Vet Radiol Ultrasound 40 (3), 246-250 PubMed.
  • Hammer A S, Couto C G, Getzy D et al (1990) Magnetic resonance imaging in a dog with a choroid plexus carcinoma. J Small Anim Pract 31 (7), 341-344 VetMedResource.