Postmortem Evaluation of 435 Cases of Intracranial Neoplasia in Dogs and Relationship of Neoplasm with Breed, Age, and Body Weight

Abstract

Background: Intracranial neoplasia of dogs is frequently encountered in veterinary medicine, but large-scale studies on prevalence are lacking.Objectives: To determine the prevalence of intracranial neoplasia in a large population of dogs examined postmortem and the relationship between breed, age, and weight with the presence of primary intracranial neoplasms.Animals: All dogs that underwent postmortem examination from 1986 through 2010 (n = 9,574), including dogs with a histopathologic diagnosis of primary (n = 227) and secondary (n = 208) intracranial neoplasia.Methods: Retrospective evaluation of medical records from 1986 through 2010.Results: Overall prevalence of intracranial neoplasia in this study's population of dogs was 4.5%. A statistically significant higher prevalence of primary intracranial neoplasms was found in dogs with increasing age and body weights. Dogs ≥15 kg had an increased risk of meningioma (odds ratio 2.3) when compared to dogs <15 kg. The Boxer, Boston Terrier, Golden Retriever, French Bulldog, and Rat Terrier had a significantly increased risk of primary intracranial neoplasms while the Cocker Spaniel and Doberman Pinscher showed a significantly decreased risk of primary intracranial neoplasms.Conclusions and Clinical Importance: Intracranial neoplasia in dogs might be more common than previous estimates. The study suggests that primary intracranial neoplasia should be a strong differential in older and larger breed dogs presenting with signs of nontraumatic intracranial disease. Specific breeds have been identified with an increased risk, and others with a decreased risk of primary intracranial neoplasms. The results warrant future investigations into the role of age, size, genetics, and breed on the development of intracranial neoplasms.

Advances in Diagnostic and Treatment Modalities for Intracranial Tumors

“…These results are similar to data in humans where an incidence of 20.59 primary CNS tumors per 100,000 human patients in the United States has been reported 6. A more accurate comparison may be based on necropsy data where intracranial/nervous system neoplasia has been reported in approximately 2–4.5% of dogs7, 8, 9 compared to approximately 2% of human patients 10. Given the practical limitations of veterinary care, it is likely that true incidence of brain tumors in dogs has been underestimated.…”

“…Given the practical limitations of veterinary care, it is likely that true incidence of brain tumors in dogs has been underestimated. Although individual studies vary, meningiomas compromise approximately 50% of primary tumors in dogs with gliomas representing 40–70% and choroid plexus tumors being the next most common tumor 7, 9, 11, 12. Secondary neoplasia accounts for approximately 50% of all intracranial tumors in dogs, with the most common tumor types being hemangiosarcoma, pituitary tumors, lymphoma, metastatic carcinoma, extension of nasal neoplasms, and histiocytic sarcoma 13.…”

“…The majority of primary and secondary intracranial tumors occur in older adult dogs with the majority over 5 years of age 11, 12, 13, 14, 15, 16. Median age for dogs with meningiomas, gliomas, and choroid plexus tumors is reported as 10–11 years, 8 years, and 5–6 years, respectively 9, 12, 15, 16. Primary tumors (particularly gliomas) occasionally may be seen in younger dogs 9, 17.…”

“…Median age for dogs with meningiomas, gliomas, and choroid plexus tumors is reported as 10–11 years, 8 years, and 5–6 years, respectively 9, 12, 15, 16. Primary tumors (particularly gliomas) occasionally may be seen in younger dogs 9, 17. No sex predisposition has been reported; however it has been suggested that brain tumors generally are overrepresented in larger breeds and meningiomas are overrepresented in Golden Retrievers, Boxers, and Miniature Schnauzers.…”

“…No sex predisposition has been reported; however it has been suggested that brain tumors generally are overrepresented in larger breeds and meningiomas are overrepresented in Golden Retrievers, Boxers, and Miniature Schnauzers. Astrocytiomas and oligodendrogliomas are highly overrepresented in specific brachycephalic breeds (Boxers, Boston Terriers, and Bulldogs), and choroid plexus tumors are overrepresented in Golden Retrievers 7, 9, 12, 15, 16, 18. Intracranial neoplasia generally is accepted to be less common in cats, although a necropsy study of approximately 4,000 cats suggested a frequency of just under 2% 19.…”