Cervical expanding hematomas in dogs: five cases.

Five puppies were presented to the Alfort National Veterinary School for a rapidly expanding, well-demarcated, subcutaneous cervical mass of a few days' duration. In all cases, previous trauma was reported. Fine-needle aspiration of the mass in each case revealed a serosanguineous fluid containing mainly erythrocytes, with a total protein concentration ranging from 3.5 to 5.2 g/dL. Coagulation tests failed to reveal any coagulation disorder. En-bloc surgical removal of the fluid-filled mass associated with short-term postoperative drainage was curative in all cases. Histopathological examination of the mass revealed encapsulated hematoma. The disease resembles chronic expanding hematoma in humans.