SIGN OF LESER-TRELAT

The sign of Leser - Trelat is usually defined as the eruptive appearan ce of numerous seborrheic keratoses or the sudden increase in the numb er and size of previous seborrheic keratoses in association with an in ternal malignancy.1 Difficulties with this definition include how ''er uptive'' is defined, what a ''significant'' increase in number and siz e of previous seborrheic keratoses is, and that the sign has been repo rted in non-''internal'' cancers such as melanomas and cutaneous T-cel l lymphomas. Nevertheless, the sign of Leser - Trelat as defined is us eful for suggesting when an underlying malignancy should be sought.