Skin Cancer Diagnosis: Reflectance Confocal Microscopy (RCM) to Replace Skin Biopsies ?

Skin Cancer Diagnosis With Reflectance Confocal Microscopy: Reproducibility of Feature Recognition and Accuracy of Diagnosis.
Farnetani F, Scope A, Braun RP, Gonzalez S, Guitera P, Malvehy J, Manfredini M, Marghoob AA, Moscarella E, Oliviero M, Puig S, Rabinovitz HS, Stanganelli I, Longo C, Malagoli C, Vinceti M, Pellacani G.
JAMA Dermatol. 2015 Oct 1;151(10):1075-80. doi: 10.1001/jamadermatol.2015.0810.

Skin biopsies can be in the form of punch biopsies in the least invasive method but to be reliable (according to many dermatopathologists), a 4mm minimal diameter is needed to be able to serve its purpose, that is not only to be able to give a diagnosis but also to rule out conditions such as skin cancer.

Doing a punch biopsy of a 4mm diameter is feasible in most areas of the body, more easily where the skin is slack.
On the face and other sensitive areas (nose…) where tissue loss is a problem, punch biopsies of a smaller diameter (2mm) are often done to minimize tissue loss.

However regardless of where the tissue is taken of and the section diameter, there will always be a scar, and getting one in visible areas can be cosmetically unacceptable, especially if the condition turns out to be benign. Also some individuals may scar poorly and could even develop keloids.

It is there that Reflectance Confocal Microsopy enters non invasive diagnostic methods (alongside dermoscopy)

Study Design
–RCM images were collected at a tertiary academic medical center in Italy (Department of Dermatology). The lesions (100) were biopsy proven and included 55 melanocytic nevi, 20 melanomas, 15 basal cell carcinomas, 7 solar lentigines or seborrheic keratoses, and 3 actinic keratoses.
-Nine dermatologists (6 of whom had ≥3 years of RCM experience) from 6 countries evaluated the lesions

Results
8 RCM descriptions showed fair to good reproducibility and were independently associated with a specific diagnosis:
–Melanoma: presence of pagetoid cells, atypical cells at the dermal-epidermal junction, and irregular epidermal architecture.
–Basal Cell Carcinoma (BCC): Aspecific junctional pattern, basaloid cords, and ulceration.
–Naevi: Ringed junctional pattern and dermal nests

The Ability to diagnose (sensitivity), around 85% but this increases to 91% with experience (percentage of sick people who are correctly identified as having the condition)
Exclusion (specificity) was around 80% regardless of the level of experience (the percentage of healthy people who are correctly identified as not having the condition)
Comments
-When a dermatologist biopsies a suspicious lesion he not only wants to confirm a cancer but most importantly want exclude it…this is still an unreliable thing with RCM.
-It would be interesting, especially in volume sensitive areas (such as the nose) to compare dermatopathology with dermoscopy-RCM so as to measure sensitivity and specificity of these combined non-invasive methods

Article selection: Prof Dr Jean-Hilaire Saurat – dermatologist. Geneva, Switzerland