P045 : Clinical characteristics of cutaneous malignant melanoma in patients under the age of 40 in Korea

Background: Cutaneous malignant melanoma (CMM) develops mainly in elderly, but we often see CMM in young patients as well in clinical practice. However, there are few studies about the clinical features of young CMM patients. Objectives: To investigate the clinical characteristics of CMM patients under the age of 40. Methods: We retrospectively reviewed medical records of CMM patients from January 2009 to June 2019 and compared the features of patients aged 10-39 with those aged 50-79. Results: Of the 341 patients with CMM, only 21 (6.1%) were between the age of 10-39 and 250 (73.3%) were aged 50-79. Frequently involved locations in age 10-39 were fingers (28.6%) and trunk (23.8%), but feet (40.4%) were preferred in age 50-79 (p=0.01). Acral lentiginous melanoma (ALM) was the most common clinical subtype in both groups (47.6% and 70.8%, respectively). Among ALMs, subungual melanoma (SUM) was more common in age 10-39 (28.6% vs. 19.0%), whereas ALM except SUM was more common in age 50-79 (17.2% vs. 53.6%). Superficial spreading melanoma (SSM, 33.3%) was also a significant subtype observed much in age 10-39 (p=0.002). There were no differences in mean Breslow thickness, lymph node metastases and staging of CMM (p>0.05). Conclusion: Compared with elderly patients, CMM in young patients showed differences in the location of the lesion and clinical subtype. More care should be paid when we encounter a young patient who is suspicious of melanoma on finger or trunk.