Confocal Microscopy

Reflectance confocal microscopy can spare biopsies in previously treated patients with extramammary Paget disease

Oriol Yélamos, MD 1, 2

1.     Dermatology Service, Memorial Sloan Kettering Cancer Center, New York, NY

2.     Dermatology Department, Hospital Clínic, Universitat de Barcelona, Barcelona

Extramammary Paget disease or EMPD is a rare skin cancer that presents with a red patch in the vulva or anus in women, and in the scrotum, penis and anus in men. Diagnosing EMPD is challenging because the entire area affected by the disease is not visible with the naked eye, or can be misdiagnosed with other skin conditions such as infection or inflammation. This is particularly important when monitoring treatment response, as treatments can irritate the skin and look identical (red patch) to residual EMPD.

Reflectance confocal microscopy or RCM is an imaging system which uses a light source that does not damage the skin and that allows to see cells on the superficial layers on the skin. RCM has been used to diagnose EMPD as one can see the cancer cells in the skin in real time. However, RCM has not been evaluated to identify if EMPD remains active after therapy. Recently we have published in JAMA Dermatology the first study using RCM in patients with previously treated EMPD. We studied 5 patients with previously treated EMPD (4 men and 1 woman). We evaluated 22 sites in the skin suspicious for EMPD using RCM and later obtaining a skin biopsy of these sites. We have found that if we saw EMPD using RCM, in all the cases (9 out 9) the biopsy revealed active EMPD. On the other hand, in the cases where we did not see cancer using RCM, there was a small chance of missing active EMPD (3 out of 13 sites). We believe this may happen because EMPD cells may form small groups of cells that can be difficult to see with RCM, especially in cases which had received therapy, or may be located too deep to be seen with RCM.

Our study has shown that RCM can be very useful to identify EMPD after treatment, and eventually if one sees EMPD on RCM, biopsies may not be necessary and can be spared in such a sensitive location. However, because there is a small chance of missing disease recurrence if RCM does not see cancer, biopsies may be needed in this setting. To sum up, we believe that by assessing previously treated EMPD with RCM, our patients will need less biopsies to know if their disease is still active or not, and whether further treatment is required.

-Publication:

Yélamos O, Hibler BP, Cordova M, Hollmann TJ, Kose K, Marchetti MA, Myskowski PL, Pulitzer MP, Rajadhyaksha M, Rossi AM, Jain M. Handheld Reflectance Confocal Microscopy for the Detection of Recurrent Extramammary Paget Disease. JAMA Dermatol. 2017 May 10. doi: 10.1001/jamadermatol.2017.0619

Confocal Microscopy To Noninvasively Detect Skin Cancer: An Emerging Technology To Avoid Unnecessary Skin Biopsy

Skin cancer is the most common type of cancer worldwide. In the United States, the incidence is rising, with over two million people diagnosed each year [1]. More cases of skin cancer are diagnosed each year than breast, prostate, lung, and colon cancer combined. The lifetime risk of developing skin cancer is estimated to be 20%[2]. Although nonmelanoma skin cancer is rarely fatal and associated with a very low mortality rate, melanoma can be highly fatal. Approximately 76,000 individuals will be diagnosed with invasive melanoma in 2012 [3]. Skin cancer can be easily cured with early detection and excision. Early detection is essential, especially for melanoma, which has a grim prognosis once it has metastasized. Today, detection requires a biopsy to definitively determine if a lesion is malignant or benign.

In vivo confocal microscopy in the daily practice of the dermatologic surgeon

CONCLUSIONS: RCM is emerging as a promising and versatile tool to assist dermatologic surgeons in the diagnosis and approach of cuta- neous tumors. Compared with dermoscopy, it has demonstrated increased sensitivity and specificity in the clinical diagnosis of melanocytic lesions and doubtful dermoscopies, and many other applications are being studied. Nevertheless, it is important to note that traditional histopathology remains the gold standard for the definitive diagnosis of skin lesions.

RCM still has many limitations, which have been mitigated as more research is performed, and the device has been improved. In 2007, a consensus conference was organized to standardize concepts, and in 2009 an Internet-based study invol- ving six reference centers was conducted to evaluate the repro- ducibility of those concepts and the derived terminology. 53, 54

The examination of a single lesion takes 5-15 minutes. A clinical examination and dermoscopy are essential to determine what should be assessed by RCM, for lesions with fewer altera- tions in the initial tests are more likely to present fewer charac- teristic findings using RCM.40

Another important limitation to be overcome with techni- cal improvements in the near future is the visualization of the dermis, given that the reflection of the light only allows viewing to a depth of 350 m only (i.e., papillary or superficial reticular dermis).

However, while dermoscopy has probably already reached its full diagnostic accuracy potential, we expect great advances in RCM in the next few years.1 As was the case for dermosco- py, we expect RCM become part of the dermatologists’ daily practice as an auxiliary method in the diagnosis and treatment of skin cancer.