A 64-year-old man presented to the emergency department with a 1-day history of hematochezia and a 3-month history of melena, during which time he experienced a 20-lb weight loss. Physical examination revealed confluent seborrheic keratoses on the patient's chest (image). Results of laboratory tests indicated microcytic anemia, with a hemoglobin level of 9.4 g/dL and a mean corpuscular volume of 78.4 μm³. Colonoscopy revealed 2 ulcerated masses within the sigmoid colon; the scope could not be advanced past the proximal lesion. Histopathologic evaluation of biopsy specimens showed ulcerated, moderately differentiated adenocarcinoma. The patient underwent resection of the segment of the colon with the masses and continued to receive surgical oncologic treatment. 

An eruption of seborrheic keratoses occurring with a malignant tumor, particularly gastrointestinal adenocarcinoma, is consistent with Leser-Trélat sign.¹ Some researchers have disputed the association of seborrheic keratoses with malignant tumors because both findings occur frequently in older individuals.² However, reports ^3-5 of Leser-Trélat sign in young individuals suggest that seborrheic keratoses may indicate underlying malignant findings.