In vivo reflectance confocal microscopy (RCM)

ما هذا؟

In vivo reflectance confocal microscopy (RCM) is a non-invasive, high-resolution imaging technique increasingly used in dermatology to visualize the skin at a cellular level in real time. It employs a low-power near-infrared laser (usually at 830 nm) to capture en face optical sections of the skin, allowing clinicians to examine structures in the epidermis and superficial dermis without the need for a biopsy.

RCM is particularly valuable for the diagnosis and monitoring of skin cancers, such as melanoma and basal cell carcinoma, as well as for evaluating inflammatory and pigmentary disorders. The images produced resemble histological sections, enabling detailed assessment of cellular morphology, architecture, and pigmentation patterns.

Because it is painless, repeatable, and rapid, RCM is useful for both clinical and research purposes, including treatment follow-up and guidance for biopsy site selection. Overall, in vivo RCM combines diagnostic precision with patient comfort, reducing unnecessary excisions and improving early detection of skin diseases.

متى يشار إلى هذا الإختبار؟

RCM is indicated when high-resolution, non-invasive imaging can aid diagnosis, guide biopsies, or monitor treatment response. It is especially useful in differentiating benign from malignant skin lesions and assessing inflammatory or pigmentary disorders without surgical intervention.

Main indications include:

  • Skin cancer diagnosis and monitoring – melanoma, basal cell carcinoma, squamous cell carcinoma.
  • Pigmentary disorders – vitiligo, melasma, post-inflammatory hyperpigmentation.
  • Inflammatory dermatoses – psoriasis, eczema, lichen planus.
  • Pre-biopsy evaluation – guiding optimal site selection.
  • Treatment follow-up – assessing therapeutic response in oncologic or inflammatory skin conditions.
  • Border assessment – mapping tumor margins before surgery or Mohs micrographic surgery.

كيف يتم تنفيذه؟

In vivo reflectance confocal microscopy (RCM) is performed using a specialized device that delivers a low-power near-infrared laser (typically 830 nm) to the skin. The patient is comfortably positioned, and the target skin area is prepared by gently cleaning it; a coupling medium, such as ultrasound gel, is applied to enhance optical contact. The device’s objective lens is placed in direct contact with the skin through a disposable window or a sterile cap.

The laser light penetrates the skin and is reflected differently by various cellular structures, particularly melanin and keratin, generating high-contrast, en face images at a resolution comparable to histology. The clinician acquires sequential optical sections, starting from the stratum corneum down to the upper dermis (approximately 200–300 µm depth), which can be reviewed in real time. Images are stored for later analysis or comparison during follow-up. The procedure is painless, quick (usually 5–15 minutes), and requires no anesthesia, allowing for repeated examinations without tissue damage.

موانع الاستعمال

In vivo reflectance confocal microscopy (RCM) is generally safe and well tolerated, with very few contraindications because it uses low-power, non-ionizing laser light and does not damage tissue.

Absolute contraindications:

  • None reported for standard clinical use.
  • Relative contraindications / situations requiring caution:
  • Infected or ulcerated skin – contact with the device may worsen infection or cause discomfort.
  • Nodular lesions – limited penetration depth may prevent adequate assessment.
  • Ulcerated lesions – poor image quality and risk of irritation.
  • Soles and palms – thick stratum corneum reduces optical penetration and image resolution.
  • Severe skin fragility (e.g., epidermolysis bullosa) – risk of mechanical trauma.
  • Recent surgical wounds – avoid scanning until healing is complete.
  • Poor patient cooperation – difficulty maintaining stillness during image acquisition.
  • Allergy to coupling medium – rare, but alternative gels or interfaces should be used.