# Epidemiology of Splenic Lesions in Dogs Undergoing Splenectomy—Pathological Characterization and Risk Factors

## TL;DR

This study examines the types and risk factors of splenic lesions in dogs, finding that non-neoplastic lesions are common, but hemangiosarcoma is the most frequent tumor with poor survival.

## Contribution

The study provides new insights into the epidemiology and risk factors of canine splenic diseases, particularly hemangiosarcoma, across breeds and demographics.

## Key findings

- Non-neoplastic lesions accounted for 54.3% of cases, with hemangiosarcoma being the most frequent neoplasm (54.5%).
- Large breeds and certain purebreds showed significantly higher risk of hemangiosarcoma.
- Dogs with hemangiosarcoma had much shorter survival times compared to those with non-neoplastic lesions.

## Abstract

Splenic diseases are common in dogs and may be either non-neoplastic or neoplastic. In this retrospective study, we examined 682 canine spleens collected between 2014 and 2023. More than half of the lesions were non-neoplastic, while hemangiosarcoma was the most frequent tumor, representing over half of all neoplasms. Large breeds and some purebreds, such as Lagotto Romagnolo, Boxer, Labrador and German Shepherd, showed a significantly higher risk of developing hemangiosarcoma. Dogs with hemangiosarcoma had much shorter survival times compared with those with non-neoplastic lesions. These findings improve our understanding of the epidemiology and prognosis of splenic diseases in the canine population.

Splenic lesions are common in dogs and can have important clinical implications due to the risk of rupture causing life-threatening hemorrhage, or, for neoplastic lesions, potential metastatic spread. This retrospective study analyzed 682 canine spleen samples submitted to the Regional Canine Cancer Registry in Umbria, Italy, between 2014 and 2023, aiming to characterize lesion types and explore associations with demographic factors and clinical outcomes. Lesions were classified as neoplastic or non-neoplastic. Non-neoplastic lesions were predominant (54.3%), mainly nodular hyperplasia, hematoma, and congestion, while neoplastic lesions accounted for 45.7%, with hemangiosarcoma (HSA) being the most frequent neoplasm (54.5%), followed by other sarcomas, lymphomas, and rare tumors. The mean age at diagnosis was 10.4 years, and medium-sized dogs living in urban areas were most affected. No significant differences in lesion type were observed between sexes or between purebred and mixed-breed dogs, although purebreds were more represented overall. HSA risk varied by size, sex, and breed, with large dogs and certain pure breeds showing elevated risk. Survival analysis revealed markedly reduced outcomes for dogs with HSA. These findings emphasize the utility of histopathologic diagnosis in guiding clinical management and provide insight into the epidemiology and prognosis of splenic lesions in dogs.