Splenic haemangiosarcoma in a cat treated with splenectomy and metronomic thalidomide.

Case summary: An 8-year-old female neutered domestic shorthair cat was referred for further investigations of lethargy, polyuria, polydipsia, hyporexia and weight loss. One month prior, the cat had been diagnosed with normotensive and non-proteinuric chronic kidney disease and a single small well-defined splenic nodule thought to represent a benign process. Specialist abdominal ultrasonography documented changes suggestive of pyelonephritis alongside a solitary splenic mass (2 cm in size). Follow-up imaging 4 weeks later showed progression of the splenic mass (3.5 cm) and a novel marked anaemia. Splenectomy and histopathology were performed, which confirmed a diagnosis of splenic haemangiosarcoma. The cat was started on metronomic thalidomide (5 mg/kg PO q24h; BOVA) 16 days postoperatively. The cat re-presented to the referring veterinary practice 169 days after splenectomy (153 days after starting metronomic thalidomide) owing to lethargy and hyporexia. Abdominal ultrasound identified a solitary hepatic mass and free peritoneal fluid; the cat was subsequently euthanased without further investigations. Relevance and novel information: This is the first published case report documenting the management of splenic haemangiosarcoma in a cat with splenectomy and metronomic thalidomide. Our observations indicate that survival time falls in line with other chemotherapeutic protocols and that thalidomide side effects were limited to mild polyphagia and moderate sedation, which was tolerated well if the drug was administered in the evening.