Feline Visceral Hemangiosarcoma

Background: Feline visceral hemangiosarcoma (HSA) is an uncommon tumor, and the clinical progression and outcome are rarely reported. Hypothesis: The prognosis of feline visceral HSA is poor because of severe clinical signs, anemia, and a high rate of metastasis. Animals: The medical records of 26 client‐owned cats with visceral HSA were reviewed. Methods: Multi‐institutional retrospective study. Results: The most common historical findings and clinical signs included lethargy, anorexia, respiratory difficulty, collapse, and vocalizing. Eighty‐two percent of cats were anemic, and aspartate transaminase was increased in 53% of the study population. Metastatic lung disease was noted in 33% of affected cats. In 75% of the cats, abdominal ultrasonography identified a specific location of HSA. However, ultrasound identification of all multifocal lesions was successful only in 3/9 cats (33%). Tumor location was identified in the following organs: liver (35%), small intestine (31%), large intestine (31%), abdominal lymph node (31%), mesentery (27%), spleen (23%), lung (19%), omentum (12%), brain (8%), pancreas (8%), and diaphragm (8%). Multifocal HSA was noted in 77% of cats. Three cats received adjuvant chemotherapy (doxorubicin). Seventy‐one percent of euthanized cats were euthanized within 1 day of diagnosis. The median survival time of the remaining cats (n = 6) was 77 days (range, 23–296 days). Conclusion and Clinical Importance: Feline visceral HSA is most often multifocal at the time of diagnosis. The prognosis appears poor, and the number of cats receiving chemotherapy is low.