Two cases of seborrheic keratosis of the external ear canal: involvement of PIK3CA and FGFR3 genes

Advances in the Etiology, Detection, and Clinical Management of Seborrheic Keratoses

Seborrheic keratoses (SKs) are ubiquitous, generally benign skin tumors that exhibit high clinical variability. While age is a known risk factor, the precise roles of UV exposure and immune abnormalities are currently unclear. The underlying mechanisms of this benign disorder are paradoxically driven by oncogenic mutations and may have profound implications for our understanding of the malignant state. Advances in molecular pathogenesis suggest that inhibition of Akt and APP, as well as existing treatments for skin cancer, may have therapeutic potential in SK. Dermoscopic criteria have also become increasingly important to the accurate detection of SK, and other noninvasive diagnostic methods, such as reflectance confocal microscopy and optical coherence tomography, are rapidly developing. Given their ability to mimic malignant tumors, SK cases are often used to train artificial intelligence-based algorithms in the computerized detection of skin disease. These technologies are becoming increasingly accurate and have the potential to significantly augment clinical practice. Current treatment options for SK cause discomfort and can lead to adverse post-treatment effects, especially in skin of color. In light of the discontinuation of ESKATA in late 2019, promising alternatives, such as nitric-zinc and trichloroacetic acid topicals, should be further developed. There is also a need for larger, head-to-head trials of emerging laser therapies to ensure that future treatment standards address diverse patient needs.

Recent advances in managing and understanding seborrheic keratosis

Seborrheic keratosis (SK) is a common benign epidermal tumor with predominance in adult patients. Whereas common SKs are more frequent in Caucasians, dermatosis papulosa nigra is more prevalent in patients with a Fitzpatrick skin type of at least 3. There seems to be a link between extrinsic skin aging and the occurrence of SK. Mutations of fibroblast growth factor receptor 3 and other signaling molecules are a frequent finding in SK lesions. However, this does not translate into any malignant potential. Viral infections are particularly common in genital lesions, although their pathogenetic relevance for SK is questionable. Different histologic and clinical subtypes have been identified. The great variability of SKs raises some difficulties in diagnosis. Dermoscopy is the preferred non-invasive diagnostic method, in particular to differentiate pigmented SKs from other pigment tumors, including cutaneous melanoma. Eruptive SKs can be a paraneoplastic condition known as the Leser–Trélat sign. New targeted cancer treatments can cause a pseudo-Leser–Trélat sign. The treatment in practice is mainly minor surgery, including cryosurgery, shave excisions, and laser-assisted removal. The medical approaches have only limited effects. Recently, two formulations for topical therapy have been evaluated: a product with 40% hydrogen peroxide (HP40) and an aqueous nitric–zinc complex. Based on clinical trials, HP40 seems to be a promising alternative to surgery, in particular for facial lesions.