Craniospinal Metastasis from a Metastasizing Mixed Tumor of Salivary Gland : Unusual Presentation

Metastasizing mixed tumors [MMT] of salivary glands are inexplicably metastasize maintaining benign histology. There is no pathologic and flow cytometric analysis criteria to predict the metastasis. MMT is known to metastasize by local implantation, vascular and lymphatic embolization after multiple surgery to local recurrences of primary tumor. However, multiple metastasis including cranium and spine occurred even without surgery to the primary tumor in this case. No pathological evidence of malignancy could be found in both primary and metastatic tumor. MMT is considered as an low grade malignancy based on clinical behavior rather than histologic evidence, such as low mortality rate, long delay of metastasis after primary lesion. Cranial metastasis is also extremely rare and only two cases have been reported. We report this unusual case with a literature review.