[Sézary syndrome and Leser-Trélat sign: a chance association?].

BACKGROUND: Leser-Trélat sign involves the combined sudden onset of seborrheic keratosis and cancer. However, some doubt surrounds the existence of this syndrome. We report a case of Leser-Trélat sign that led to the discovery of Sézary syndrome. PATIENTS AND METHODS: A 59-year-old woman presented generalized pruritus with secondary appearance of multiple seborrheic keratosis. Leser-Trélat sign was diagnosed and 20 months later, Sézary syndrome was discovered. Extracorporeal photopheresis was initiated, after which there was a marked reduction in the patient's pruritus, erythroderma and numbers of seborrheic keratoses and Sézary cells. DISCUSSION: Leser-Trélat sign is often associated with gastric carcinoma or lymphoproliferative tumours. Rampen and Schwengle [J Am Acad Dermatol 21 (1989) 50-5] have thrown doubt on this entity because of the "subjective" definition, the frequent dissociation between the course of the tumour and that of the seborrheic keratosis, the disparity between the frequency with which rapid onset seborrheic keratosis is seen and the rarity of cases in which this phenomenon reveals a tumour and the absence of association with any specific type of malignancy. The time between diagnosis of Sézary syndrome and cutaneous symptoms of Leser-Trélat sign appears very long in the present case. In the absence of any established physiopathology, it is impossible to prove any direct link between these two syndromes. Leser-Trélat sign remains controversial. Knowledge of its pathogenesis could help determine whether Leser-Trélat sign should or should not be considered a paraneoplastic syndrome.