Leser–Trélat sign: current observations

Leser–Trelat sign is a cutaneous manifestation that presents with rapid onset of multiple seborrheic keratoses on the trunk and extremities. In the majority of cases, seborrheic keratoses increase in number within short periods (usually within 6 months). Seborrheic keratoses are commonly seen in elderly people; however, Leser–Trelat sign is important because it may be a clue to the discovery of occult internal malignancies. Adenocarcinomas involving the stomach, intestine and breast are commonly associated with Leser–Trelat sign, however, hematological malignancies have also been detected. Several reports have shown that Leser–Trelat sign is associated with benign neoplasms. Although the etiology of Leser–Trelat sign is largely unknown, several speculations have been proposed. EGF and TGF-α are derived from the original tumor cells, while EGF-receptor (EGF-R) is expressed on the epidermis. This suggests that the development of seborrheic keratoses may be accelerated via EGF-R-mediated signaling pathways. ...