dermatoscopie

Dermatoscopy, also known as dermoscopy (dermatoscopie in French), is a noninvasive imaging technique used to examine skin lesions. It uses a handheld instrument called a dermatoscope to illuminate and magnify lesions, revealing subsurface structures such as pigment networks, vascular patterns, and other microscopic features not visible to the naked eye. The technique aids in distinguishing benign from malignant lesions and in monitoring known lesions over time.

Devices combine a magnifier (typically 10×) with illumination; there are noncontact polarized systems and contact dermoscopy that may use a coupling fluid. Modern options include digital dermoscopy, which stores images for serial comparison and computer-assisted analysis. Polarized and nonpolarized light reveal different structures; sometimes immersion fluids reduce surface reflection.

In practice, dermatoscopy is used primarily for evaluation of pigmented lesions to support melanoma screening and to classify nevi and other tumors (basal cell carcinoma, seborrheic keratosis) and inflammatory conditions. Interpretation relies on pattern analysis and recognition of features such as pigment network, dots and globules, streaks, and blue-white structures, as well as vascular patterns. Training and experience improve diagnostic accuracy, and dermatoscopy is typically used to decide whether a lesion should be biopsied.

Limitations include operator dependence, the need for adequate training, and imperfect specificity. It complements, but does not replace, histopathological examination. Guidelines emphasize structured training, standardized terminology, and, for digital dermoscopy, regular calibration and image quality checks.

Overall, dermatoscopy has become a standard tool in dermatology for the early detection of melanoma and the characterization of pigmented and nonpigmented skin lesions, improving diagnostic confidence and reducing unnecessary biopsies when combined with clinical examination.