Lesion diameter and area of melanoma of the lentigo maligna type (LM) are poorly associated with the presence of invasion, according to a study published in the May issue of the Journal of the American Academy of Dermatology.

Cristian Navarrete-Dechent, M.D., from the Memorial Sloan Kettering Cancer Center in New York City, and colleagues evaluated whether clinical size was a predictor of invasion in LM and subclinical extension among 600 consecutive cases of LM (2006 to 2019; mean age of 65.9 years; 62.8 percent men).

The researchers found that mean overall clinical diameter was 10.76 mm for in situ lesions and 13.17 mm for invasive lesions. The mean LM clinical area was 128.32 mm² for in situ lesions versus 200.14 mm² for invasive lesions, which was not statistically significant. No other clinical variables, including age, sex, anatomic location, or laterality, predicted invasion. The median margin required for complete removal increased with LM clinical area in a quantile regression analysis.

"LM can present with variable clinical size; however, the presence of invasion is not reliably predicted by clinical size or other clinical characteristics," the authors write. "Larger lesions tend to have more subclinical extension and, therefore, may need additional surgical margins for clearance."

One author disclosed financial ties to pharmaceutical and biotechnology companies.

Abstract/Full Text (subscription or payment may be required)