Clinical examination
On physical examination, the horse was in good body condition. All clinical parameters were within normal range. A firm swelling was palpable at the proximomedial aspect of the left metacarpus, measuring approximately 10 cm in length, 9 cm in width and 6 cm in thickness (Fig 1a) . Upon palpation, the skin was intact and could be moved separately from the underlying mass, which seemed firmly attached to the bone and not painful on palpation.