[Tumoral collision: cancer metastases within a second neoplasm].

A case report of epithelial carcinoma of the inferior lip which spread in cervical lymph nodes previously affected by a chronic lymphocitic leukaemia, is presented. The coexistence of both histological findings in some of the nodes (collision tumor) is remarked. We have made a review of the scanty literature about metastases on second tumors and compared and commented those features.