The sign of Leser-Trelat refers to the appearance of freckles or seborrheic keratoses associated with an underlying malignancy, typically an adenocarcinoma.


Features of the sign of Leser-Trelat:

(1) The relatively sudden appearance of multiple freckles and/or seborrheic keratoses.

(2) The presence of an underlying malignancy, typically an adenocarcinoma of the gastrointestinal tract.

(3) The lesions are sometimes pruritic.

(4) Patients may also develop acanthosis nigricans.


In the classic case, the skin lesions appear in unblemished skin, free of skin lesions. In some cases the lesions may occur in an area with pre-existing lesions, with an increase in both size and number.


I saw a case of an elderly woman with 2 large facial seborrheic keratoses about the size of a quarter (one proven by excisional biopsy) and atypical carcinoid tumor of the lung. When the primary and solitary metastatic focus were excised, the remaining seborrheic keratosis shrank and then disappeared over a two week period.


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