Chromosomal studies of a cultured parotid sebaceous lymphadenoma showe
d two abnormal cell groups, one with trisomy 9 (15% of the metaphases)
and one with inconsistent structural deviations (10%). FISH analysis
showed that the trisomic clone was actually larger (36%) than that rev
ealed by chromosomal studies. The sebaceous lymphadenoma represents th
e fourth type of benign salivary gland tumor to show clonal chromosoma
l deviations.