An 11-year-old male castrated mixed breed dog presented to the primary veterinarian (rDVM) for lethargy, brown urine, and pale mucous membrane before he was referred to Cornell University Hospital for Animals for splenectomy. Physical examination of this patient revealed pertinent abnormalities including mildly pale mucous membranes and a palpable abdominal mass. A complete blood count (CBC) and serum chemistry revealed abnormalities consistent with the patient's previously diagnosed hypothyroidism, but no other clinically significant abnormalities. An abdominal ultrasound revealed a large irregular splenic mass. A splenectomy was performed. The whole spleen and a nodule on the omentum were submitted for histopathology. Even though hemangiosarcoma (HSA) was highly suspected, the histopathology result was consistent with a splenic hematoma and omental daughter spleens. The dog was clinically doing well three months after the surgery, but his blood work at the rDVM showed mild anemia and hypoalbuminemia. No further diagnostics were pursued at this point. Using this case as a framework, the characteristic presentation of splenic HSA, common diagnostic findings, and long-term outcome of patients with splenic hematoma after splenectomy are reviewed.