Salivary mucocele with osseous metaplasia in a dog.

A 4-year-old, male, dachshund was referred to a certain local veterinary hospital because of a soft and fluctuant swelling in the left upper cervical region. The swelling was surgically removed and appeared to be filled with bloody mucus. Grossly, the swelling was identified as salivary mucocele and showed small multifocal whitish ossified tissue on its surface. Microscopically, the wall of salivary mucocele appeared as granulation tissue surrounding mucin, which was composed of loose edematous and vascularized connective tissue containing chronic inflammatory cells such as lymphocytes, plasma cells and macrophages. Characteristically, present case had ossifying components formed by metaplastic spindle cells in the wall of salivary mucocele. Therefore, the present case was diagnosed as salivary mucocele with osseous metaplasia in a dog.