Splenomegaly in small-breed dogs: 45 cases(2005-2011).

OBJECTIVE To assess causes of splenomegaly and postsurgical outcomes in small-breed (ie, < 16-kg [< 35.2-lb]) dogs that underwent splenectomy and evaluate associations among malignant disease, hemoperitoneum, and survival time in these patients. DESIGN Retrospective case series. ANIMALS 45 client-owned dogs. PROCEDURES Medical records of 2 veterinary facilities were reviewed to identify small-breed dogs that underwent splenectomy and had a histologic diagnosis recorded. Data analyzed included signalment, diagnosis, presence or absence of hemoperitoneum, and survival time. RESULTS 21 dogs had malignant neoplasia and 24 had benign splenic diseases. Hemangiosarcoma was the most common malignancy (14/21 [67%] dogs) and lymphoid nodular hyperplasia, hematoma, or extramedullary hematopoiesis (alone or in combination) was most commonly diagnosed in dogs with benign disease (17/24 [71%]). Wheaton Terriers were significantly more likely to have malignant splenic disease than were dogs of other breeds. Malignant splenic disease and the presence of hemoperitoneum had significant negative associations with survival time. Malignant disease was not significantly associated with the presence of hemoperitoneum. CONCLUSIONS AND CLINICAL RELEVANCE Causes for splenomegaly and survival times were similar to those previously reported for populations that primarily included large-breed dogs. There were approximately equal numbers of benign and malignant causes for splenomegaly in this population. Results suggested that Wheaton Terriers with splenomegaly had a higher likelihood of malignant neoplasia than other breeds and that hemoperitoneum may not be a significant predictor of malignancy in small-breed dogs. However, further research including a larger number of dogs is needed to confirm these findings. (J Am Vet Med Assoc 2017;250:1148-1154).