Multicentric oral plasmacytoma in 3 dogs.

Oral extramedullary plasmacytomas (EMP) are locally aggressive tumors in the dog that rarely metastasize. They represent 5.2% of all canine oral tumors and 22.0 to 28.0% of all EMPs diagnosed are in the oral cavity. EMPs consist of neoplastic plasma cells that do not arise from the bone marrow. No relationship between EMP and the development of multiple myeloma has been determined in dogs. Complete surgical excision is the primary treatment for this neoplasm and is usually curative. Multiple oral EMPs within the same patient have been rarely reported with tumors arising in the same location in the mouth. To the authors' knowledge, multicentric oral EMP, as described in the following cases, has not been reported in the dog.