Seborrheic keratosis-like melanoma: a diagnostic challenge.

This article summarizes the main epidemiologic and diagnostic features of seborrheic keratosis-like (SK-like) melanoma. We performed a review of the current literature. The real and current incidence and prevalence of SK-like melanoma are unknown. Many lesions are misdiagnosed and not excised with histopathologic confirmation, or excised without an appropriate surgical approach due to a benign clinical and dermoscopic appearance. SK-like melanoma presents both melanoma and SK features. SK-like melanoma and SK are often clinically indistinguishable even for experienced dermatologists. Clinically, it develops as a black-dark brown or light slightly elevated, papule, nodule or plaque with rapid growth and a regular or irregular shape. SK-like melanoma presents melanocytic and nonmelanocytic dermoscopic features. Irregular dark-brown dots/globules, a blue-grayish veil, streaks, irregular pigmentation or network and brown lines point to a melanoma diagnosis. Among the nonmelanocytic features, milia-like cysts and comedo-like openings have been highlighted. The association of polarized and nonpolarized dermoscopic techniques is more accurate for studying the dermoscopic features of SK-like melanoma. If the dermoscopic features are unclear, further investigations with reflectance confocal microscopy (RCM) or biopsy with histologic examination are essential. SK-like melanoma is a dermatologic challenge. Careful clinical and dermoscopic evaluation favor a correct diagnosis. In unclear cases, it is important to perform a biopsy with histologic examination to confirm the correct diagnosis.