WEDNESDAY, June 12, 2024 -- Melanomas arising in giant pigmented nevi (MGPNs) occur at a younger age than other melanomas and have high disease-specific (DSS) and overall survival (OS) rates, according to a study published online June 4 in the Journal of the American Academy of Dermatology.

Nelson Ugwu, M.D., from the Harvard Combined Dermatology Residency Training Program in Boston, and colleagues utilized the Surveillance, Epidemiology, and End Results database to analyze data on MGPNs diagnosed between 2000 and 2020.

The researchers identified 1,666 MGPNs during the study period, 57 percent of which were diagnosed in men. The trunk, upper limbs and shoulders, and head and neck were the most common anatomical sites involved (47.8, 22.6, and 14.7 percent, respectively). MGPN diagnoses occurred at a younger age than other melanomas, with 27 percent of MGPNs diagnosed in patients younger than 40 years compared with 12 percent of all melanomas diagnosed in patients aged 44 years and younger. The median age at diagnosis was 52 years for MGPNs versus 66 years for all melanomas. Seventy-one percent of tumors were localized at the time of diagnosis, with regional and distant disease seen in 7 and 1.4 percent, respectively. The five-year DSS was 94 percent (92 and 97 percent in male and female patients, respectively), similar to that seen for all melanomas. The five-year OS rate was 90 percent (87 and 94 percent for male and female patients, respectively). MGPNs were more aggressive for patients diagnosed in childhood, with increased odds of regional disease and metastatic disease (odds ratios, 4.3 and 14.1, respectively).

"Further studies are needed to identify risk factors that may influence transformation of giant melanocytic nevi into malignant melanomas, or portend a more aggressive course," the authors write.

One author disclosed ties to Apogee and Skin Analytics.