Oesophageal leiomyosarcoma in dogs: surgical management and clinical outcome of four cases.

Oesophageal leiomyosarcoma has yet to be reported in dogs. This retrospective case series describes the case management and clinical outcome of four dogs with oesophageal leiomyosarcoma treated by marginal excision alone. Histological features used to determine tumour grade included capsular invasion, percent necrosis, pleomorphism and mitotic rate. All tumours were designated grade 1 leiomyosarcoma. Excision of all grossly evident tumour tissue was achieved in two of the four cases; however, histopathologic evaluation showed tumour cells at the surgical margins in one of these two cases. Two dogs had grossly incomplete excision. Two dogs died from unrelated conditions, one 3 years and 5.5 months after surgery, the other at 65 days. One dog had persistent mega-oesophagus and was lost to follow-up 388 days after surgery and one dog is still alive (last follow-up 405 days after surgery). Despite large tumour size and incomplete excision, surgical removal of low-grade leiomyosarcomas can result in long-term resolution of clinical signs.