Leser-Trelat sign: can it follow COVID-19 infection?

ABSTRACT

Seborrhoeic keratosis is a benign brownish-black skin lesion that is almost always seen in middle-aged and elderly populations. The sudden onset and rapid increase in size and/ or number of seborrhoeic keratoses is called the Leser-Trelat sign, suggesting a paraneoplastic manifestation of internal malignancy. However, eruptive seborrhoeic keratoses are also described in some nonmalignant conditions such as human papillomavirus infection and HIV infection. Herein, we report a case with Leser-Trelat sign in a patient following COVID-19 infection. A 50-year-old man presented to our dermatology clinic complaining of the sudden appearance of multiple warty-like lesions on his back, which had occurred 2 months after recovery from COVID-19 infection. According to his medical history, the patient presented with cough, fever and dyspnoea about 2 months prior to the appearance of his skin lesions. He was referred to a health centre, where a nasopharyngeal swab was taken, and his polymerase chain reaction test for COVID-19 was positive. In addition, bilateral patchy ground-glass infiltration was reported in his high-resolution computed tomography (HRCT) scan, all in favour of COVID- 19 infection. The patient was then treated with acetaminophen, dexamethasone (intramuscular injection), salmeterol and a fluticasone inhaler, and his symptoms improved. Two months after recovery from his mild COVID-19 infection, several small asymptomatic pigmented verrucous papules appeared on his back. Physical examination revealed multiple rough, oval-shaped, brownish papules of varying size. Dermatoscopy of the lesions was also performed. Both clinical and dermoscopic findings were in favour of seborrhoeic keratosis. In order to reach a final diagnosis, a skin biopsy was performed, and microscopic examination of the biopsy specimen showed hyperkeratosis and well-defined epidermal hyperplasia composed mainly of the proliferation of benignlooking basaloid cells and fewer squamoid cells and horn cysts and increased melanin, mostly at the dermoepidermal junction. The dermis showed no significant change. Based on the above findings, the patient was diagnosed with eruptive seborrhoeic keratosis. To determine the possible cause of this eruption, the patient was further evaluated. In his past medical history, he was generally healthy before his COVID-19 infection and had no history of comorbidities. The patient underwent a workup to rule out any internal malignancies. Laboratory tests revealed normal results and included a complete blood count, liver and kidney function tests, electrolytes, prostate-specific antigen and urine analysis. Gastrointestinal endoscopy and colonoscopy ruled out any gastrointestinal malignancy. Chest X-ray and HRCT revealed no malignant lesion. In addition, the patient's abdominopelvic sonography was normal. The patient had no family history of similar skin lesions and gave no history of any chronic inflammatory skin diseases or viral conditions. Therefore, the appearance of the Leser-Trelat sign after COVID- 19 infection was a possibility in this patient. The role of transforming growth factor-alpha and tumour necrosis-alpha in eruptive seborrhoeic keratoses, as well as in COVID-19 infection, can be a common area of interest to explore in the aetiology of this entity.