IS PLEOMORPHIC ADENOMA OF THE SALIVARY-GLANDS A TUMOR OF CONGENITAL OR VERY EARLY ORIGIN - EVIDENCE FROM CYTOGENETICAL OBSERVATIONS IN 2 CASES

The cytogenetical observations in a cultured parotid pleomorphic adeno ma are presented. The patient had received treatment with X-rays for a n infectious disorder in the same region about 50 years earlier. A pol yclonal chromosomal pattern was disclosed with predominance of unique structural deviations. We have observed a similar chromosomal picture in a previously reported adenoma. This patient had also been treated w ith X-rays about 50 years earlier. The findings in these two cases sug gest that many, perhaps all, pleomorphic adenomas are either congenita l or arise very early in life. Their clinical manifestation at strongl y varying time points in adulthood would then depend on accumulated mu tational effects of unknown oncogenic agents.