Can the very sudden and widespread appearance of seborrhoeic keratoses over a few weeks, with new lesions continuing to emerge, be compatible with the Leser-Trélat sign? What studies or tests would be advisable to distinguish a benign presentation from a possible paraneoplastic syndrome?

Hello,

Yes. A truly sudden and widespread appearance of seborrhoeic keratoses — especially when new lesions continue to emerge over the course of a few weeks or months — may bring to mind what is known as the Leser-Trélat sign.

However, it is important not to be alarmed: this is an uncommon and, moreover, a debated sign. Seborrhoeic keratoses are extremely common benign lesions and can increase considerably with age without any malignant disease being present.

What raises suspicion?

What raises suspicion is a very striking change compared to the usual situation: the appearance of numerous lesions over a short period of time, rapid growth, intense itching and, in particular, the association with symptoms such as unexplained weight loss, reduced appetite, marked fatigue, anaemia, digestive bleeding or persistent changes in bowel habit.

What investigations are advisable?

There is no specific test that can confirm or rule out the Leser-Trélat sign. The first step would be to carry out a thorough medical examination of the skin and a dermatoscopy to confirm that the lesions are indeed seborrhoeic keratoses. If any of them show atypical features, a biopsy may be indicated.

If the appearance has been truly explosive and there is no obvious explanation, it may be reasonable to complete the work-up with a full blood count, liver and kidney function tests, blood glucose, ferritin and inflammatory markers (CRP/ESR), along with a full clinical history and general physical examination.

Further investigations should subsequently be tailored to the individual based on age, sex, family history, risk factors and symptoms, while also ensuring that the usual cancer screening programmes are up to date. I do not consider it appropriate to routinely perform a whole-body CT scan or multiple tumour markers in an asymptomatic person solely because they present with seborrhoeic keratoses.

The true Leser-Trélat sign has been described primarily in association with gastrointestinal adenocarcinomas, particularly gastric ones, although it has also been reported in connection with other tumours.

Therefore, an exceptionally rapid and widespread appearance does warrant a medical assessment and investigation, but it does not automatically mean that cancer is present.

Kind regards,

Dr Florian André Vallecillo Cabrera