Ectopic Splenic Tissue Mimicking Malignant Neoplasia in a Dog

A 14-year-old neutered male dog with a history of splenectomy for hemoabdomen secondary to a benign splenic lesion was evaluated for hyporexia and vomiting. Abdominal ultrasonography demonstrated multiple large, irregular, mildly vascularized mesenteric masses with heterogeneous echotexture and multifocal cavitated regions. Histopathologic evaluation confirmed ectopic splenic tissue with extensive hematoma formation and no evidence of malignancy. This case highlights the potential for benign ectopic splenic tissue to closely mimic aggressive neoplasia on imaging and emphasizes the importance of including ectopic splenic tissue in the differential diagnosis of cavitated abdominal masses, particularly in dogs with a history of hemoabdomen and/or splenectomy.