Postirradiation malignant salivary gland tumor.

Information concerning the relationship between salivary gland tumors and prior exposure to radiation for benign conditions or by accident is slowly being gathered. As yet, no statistical confidence can be established in this relationship. Very likely, this confidence will require studies akin to those done on the problem of thyroid cancer and irradiation. Including the case reported here, 50 tumors of the salivary glands have been reported to have followed prior radiation exposure. Twenty-three of these tumors have been malignant, with the mucoepidermoid carcinoma the most frequent histological type. The latent period in salivary tissues is 20 or more years.