Hypercalcaemia as a suspected paraneoplastic syndrome to feline intestinal leiomyosarcoma

A 13‐year‐old, female, neutered, domestic, shorthair cat presented with a history of weight loss and vomiting. An intra‐abdominal mass was palpated during clinical examination, and total hypercalcaemia was noted on biochemistry. Imaging findings were consistent with a jejunal mass, which was surgically resected, and an end‐to‐end anastomosis was performed. No other obvious signs of metastatic disease were observed. The hypercalcaemia resolved after 14 days, and histopathology results identified a leiomyosarcoma, which was confirmed by immunohistochemistry staining. After 200 days, the patient returned with signs of hyporexia, weight loss and vomiting. Abdominal imaging evidenced a gastric wall mass and based on the previous clinical history, metastatic spread of the initial leiomyosarcoma was suspected, and the patient was euthanased. This is the first report of intestinal leiomyosarcoma associated with hypercalcaemia.