Chapter 1: Dermoscopy From A to Z

SYNONYMS

• Dermatoscopy.

• Skin surface microscopy.

• Epiluminescence microscopy (ELM).

• Digital dermoscopy/digital ELM.

• Auflichtmikroscopie (German).

• Dermoscopia/dermatoscopia (Spanish).

• Dermoscopy and dermatoscopy are used interchangeably by experienced dermoscopists and in the literature.

DEFINITION

• Dermoscopy is an in vivo, noninvasive technique in which oil or fluid (eg, mineral oil, gel, alcohol, water) is placed on the lesion.

  • Fluid eliminates reflection of light from the surface of the skin, allowing visualization of color and structure in the epidermis, dermoepidermal junction, and papillary dermis.

  • The color and structure visualized cannot be seen with the naked eye or with typical magnification that clinicians use.

  • Polarizing light and digital instrumentation do not require fluid.

• When using polarized light dermoscopy:

  • Light from a polarized light source penetrates the stratum corneum with less scatter.

  • A second polarizer screens out scattered surface light, resulting in the physician seeing primarily light from the deeper structures.

  • This removes the need for contact with the skin and the need for immersion fluids, resulting in faster examination times.

• There is noncontact and contact polarized dermoscopy.

  • Gels can be used with contact polarized dermoscopy to enhance the appearance of vessels or eliminate the negative effects of dry skin.

• There is contact nonpolarized dermoscopy.

  • Some criteria can be better visualized with polarized dermoscopy, such as small vessels and blue-white color.

  • Some criteria can be better visualized with nonpolarized contact dermoscopy, such as milia-like cysts seen in seborrheic keratosis and melanocytic lesions.

  • Crystalline structures (aka shiny white structures) can only be seen with polarized dermoscopy.

  • All the criteria needed to make a dermoscopic diagnosis can be made using any form of the technique.

BENEFITS OF DERMOSCOPY

• Helps to differentiate melanocytic from nonmelanocytic skin lesions.

• Helps to differentiate benign from malignant skin lesions.

• With dermoscopy, the sensitivity to diagnose melanoma is 85% and better compared with 65% to 80% when the technique is not used.

• Increases the diagnosis of early melanoma.

• Increases the diagnosis of amelanotic and hypomelanotic melanoma.

• Increases the diagnosis of melanoma incognito (clinically false-negative melanoma).

• Increases the diagnosis of inflammatory lesions (ie, lichen planus, psoriasis, seborrheic dermatitis, rosacea, discoid lupus erythematosus, granulomatous diseases).

• Increases the diagnosis of infestations (eg, scabies, head lice, crab lice).

• Increases the diagnosis of alopecia (eg. androgenic alopecia, alopecia areata) and hair shaft pathology (eg, monilethrix, trichorrhexis invaginata).

• Helps to avoid unnecessary surgery.

• Helps to plan surgery.

• Helps to work better with a pathologist (asymmetrical high-risk criteria, collision tumors, dermoscopic-pathologic correlation).

• Patient reassurance.

• Allows for follow-up of patients with a single nevus or multiple nevi digitally to find changes over time.

DERMOSCOPIC DIGITAL MONITORING

• There are pigmented skin lesions that are not high-risk enough to warrant immediate histopathologic diagnosis, yet not so banal that there is no concern at all.

• There are melanomas that do not appear to be high-risk clinically or with dermoscopy.

• They are only diagnosed after monitoring for dermoscopic changes over time ...