Before removing lesion, investigate LM

A recent study found that cosmetic treatments performed on presumed benign pigmented lesions later found to be lentigo maligna (LM) is not an uncommon occurrence, underscoring the need for individuals performing cosmetic procedures to be more vigilant in thoroughly investigating suspicious lesions. An increased awareness of these challenging lesions could reduce inadvertently performing cosmetic procedures on lentigo maligna and perhaps aid in earlier diagnosis.

Typically occurring in sun-damaged skin of the head and neck, LM is an early stage of melanoma with its malignant cells confined to the epidermis. This lesion however can often clinically resemble benign pigmented lesions, which can lead to misdiagnoses and further, to inadvertently performed cosmetic treatments on LM.

“Lentigo maligna can be a difficult diagnosis as it occurs in the background of extensive sun-damage and often amongst a field of many benign solar lentigines,” says Brian P. Hibler, M.D., Memorial Sloan Kettering Cancer Center, New York.

“It is a challenging diagnosis to make, even for experienced dermatologists, as they share many overlapping features with benign pigmented lesions such as macular seborrheic keratosis, pigmented actinic keratosis, and solar lentigines. Nine in 10 fair-skinned individuals over age 60 have benign solar lentigines, which are a common cosmetic concern, highlighting the need for clinicians to fully evaluate presumed benign pigmented lesions before embarking on cosmetic treatment,” he adds.

Dr. Hibler and fellow colleagues recently conducted a study to determine the prevalence of biopsy-proven LM that presented for definitive treatment following a history of cosmetic treatment, and to evaluate if prior cosmetic treatment complicates management and prognosis.

The retrospective study reviewed all consecutive cases of biopsy-proven LM that presented to a dermatologic surgery practice at a cancer center for management between 2006 and 2015 in which prior cosmetic treatment and biopsies were recorded. Those cases that were previously treated solely with surgical excision or with topical imiquimod were excluded in the analysis. Medical records were reviewed for demographic data, clinical characteristics, histologic features and surgical outcomes.

Findings

It was found that 503 patients were treated for biopsy-proven lentigo maligna in the reviewed time frame. Of these, 7.4% (37/513) of patients had a history of prior cosmetic treatment of their lesion. The average size of the lentigo maligna was 1.9 cm in longest clinical diameter (range: 0.3 - 5.5 cm), with all but two of the lesions located in the head and neck region.

Data showed that prior cosmetic treatments included cryotherapy (73%), laser treatment (29.7%), topical bleaching agents (18.9%), and electrodessication and/or curettage (5.4%). Ten patients (27%) were treated with two or more treatment modalities. Eight patients (21.6%) reported a prior benign biopsy. Six patients (16%) had invasive disease (depth 0.2 mm – 1.25 mm); two on initial biopsy and four detected upon complete excision. The average margin required for clearance was 9.1 mm.

Takeaways

While it is unreasonable to biopsy every pigmented lesion prior to cosmetic treatment, Dr. Hibler says that all pigmented lesions warrant thorough clinical and dermoscopic evaluation. When evaluating pigmented lesions, clinicians should use whatever diagnostic tools they have at their disposal: 

Take a thorough history, compare to prior photographs, use dermoscopy or confocal microscopy, and if indicated, biopsy the potentially concerning areas.

“Clinicians should discuss further evaluation if cosmetic treatments are being considered but there are subtle features suspicious for lentigo maligna. However, if patients are seeking cosmetic treatments from providers not familiar with the subtle aspects of lentigo maligna they may not be aware of such features. The findings in this study reinforce the importance of going to individuals appropriate trained in evaluating skin lesions and cosmetic concerns,” Dr. Hibler says.

Reflectance confocal microscopy is emerging as a valuable tool for noninvasively evaluating pigmented lesions on cosmetically sensitive areas of the head and neck. It is used to help evaluate the lesion and margins prior to biopsy, to hone in on the areas most suspicious for malignancy and invasion. While dermoscopy may help render a correct diagnosis, confocal microscopy allows for imaging of the skin in vivo to evaluate for invasive disease and identify the ideal areas to biopsy. It can also help evaluate margins pre-surgically to better inform the clinician and patient what to expect and help plan for reconstruction. According to Dr. Hibler, incorporating dermoscopy or referring to a center with reflectance confocal microscopy can provide reassurance if a lesion is benign prior to treating cosmetically.

“Lentigo maligna can be a difficult diagnosis to make, its annual incidence is increasing, and we are amidst an aging population with a growing interest in cosmetic procedures to reverse the signs of aging. Understanding the natural progression of pigmented lesions on sun-damaged skin can help when evaluating lesions before cosmetic treatment. Patients should be educated that if their lesion does not resolve following cosmetic treatment, or if these are any changes over time, they should return to their dermatologist for regular follow-up. Clinical repigmentation following cosmetic treatment may also be a clue for further assessment,” Dr. Hibler said.

Disclosures:  Dr. Hibler reports no relevant disclosures.