[Hematogenous metastases of benign pleomorphic adenomas of the salivary glands (author's transl)].

Hematogenous metastases of benign pleomorphic adenomas are exceptionally rare. In three secure reports of the world literature metastases occurred in lung, liver or bone after operation of a benign pleomorphic adenoma with the greatest interval of twenty-two years between operation and metastases. This will be interpreted as implantation-metastases. All other observations represented secondary carcinomas in pre-existing pleomorphic adenomas. The morphological criterias of an accurate classification are explained. A number of reports of the literature about metastases of benign pleomorphic adenomas deals with misinterpretations of secondary adenomas in pre-existing pleomorphic adenomas.