FGFR3 mutations have also been detected in 40% of seborrheic keratoses (SKs) of the hyperkeratotic and acanthotic subtype, which are very common benign skin tumors.
Although acanthosis nigricans, a benign skin tumor, has been found in some syndromes associated with germinal activating mutations of FGFR3, the role of activated FGFR3 in the epidermis has never been investigated.