Abstract / Summary
Abstract Splenic lesions are common in dogs and are frequently associated with suspicion of malignancy. However, the applicability of the traditional “two-thirds rule” across different canine populations remains uncertain. This study aimed to characterize the epidemiological, clinical, and histopathological features of dogs undergoing splenectomy and to investigate hemoperitoneum as a potential indicator of splenic malignancy. Medical records and histopathological reports from 228 dogs submitted to splenectomy between 2008 and 2024 were retrospectively reviewed, comprising 293 splenic lesions. Epidemiological, clinical, ultrasonographic, and histopathological data were analyzed using descriptive and association analyses, and odds ratios (ORs) were calculated. The study population consisted predominantly of middle-aged to older dogs, with a median age of 10 years, large-breed dogs (53.9%), and mixed-breed dogs (50.4%). Non-neoplastic and neoplastic lesions accounted for 50.5% (148/293) and 49.5% (145/293) of diagnoses, respectively. The most frequent diagnoses were hemangiosarcoma (HSA) (n = 72), splenic infarction (n = 32), nodular hyperplasia (n = 24), extramedullary hematopoiesis (n = 23), lymphoma (n = 22), and hematoma (n = 22). Free abdominal fluid was detected ultrasonographically in 76/228 (33.3%) dogs, of which 45 underwent laboratory evaluation of the effusion. Dogs with hemoperitoneum had 4.4 times greater odds of having neoplastic splenic lesions (OR = 4.40; 95% CI: 1.82–10.66) and 11.5 times greater odds of HSA compared with other splenic diagnoses (OR = 11.49; 95% CI: 4.84–27.28). These findings indicate that hemoperitoneum is a clinically relevant indicator of splenic malignancy, particularly HSA, and may aid preoperative risk stratification. The lower neoplasia frequency observed challenges the broad applicability of the traditional “two-thirds rule".