Chan Yuin-Chew, Giam Yoke-Chin
National Skin Centre, Singapore.
J Am Acad Dermatol. 2006 May;54(5):778-82. doi: 10.1016/j.jaad.2006.02.063. Epub 2006 Mar 29.
The lifetime risk of developing melanoma in Caucasian patients with large congenital melanocytic nevi (LCMN) is estimated to be between 4.5% and 10%. Cohort studies of LCMN and the risk of melanoma development in an Asian population are not available.
We sought to determine the risk of melanoma development in a retrospective cohort of patients presenting with LCMN to a dermatology tertiary referral center in Singapore from January 1989 to December 2004.
Patients with congenital melanocytic nevi (CMN) that covered at least 5% of the body surface area were included in the study. Data were obtained from electronic records and photographic documentation. A search for malignancy was done using the National Cancer Registry database.
In all, 39 patients (23 male and 16 female) met the study criteria of LCMN; 15 of 39 patients also met the criteria of having a giant CMN (ie, a CMN that is predicted to be at least 20-cm diameter in adulthood). There were 29 Chinese, 6 Malay, 1 Indian, and 3 Caucasian patients. Their ages ranged from 23 months to 60 years (mean 18.8 years). They presented at a mean age of 26 months and were followed up for an average of 16.9 years. The size of the LCMN ranged from 5% to 40% of body surface area, with a mean of 12.2%. The most common sites were the back (54%), lower limb (28%), and abdomen (26%). Satellite lesions were present in 22 patients. Magnetic resonance imaging of the head or thoracolumbar spine was performed in 7 patients with LCMN on the scalp/face or back, respectively; all produced normal findings. Only one patient was treated: he had carbon-dioxide laser ablation and Q-switched neodymium:yttrium-aluminum-garnet laser treatment of a small part of his LCMN. Skin biopsies were done in 5 patients who had developed nodules; histology showed no evidence of malignancy. No patients had developed any form of malignancy.
The addition of 3 adult patients born before the start of the cancer registry may have led to survivor bias. The small sample size did not allow a precise estimate of the risk of melanoma development in our study population.
The risk of melanoma development in LCMN within a predominantly Southeast Asian cohort appears to be very low. Prophylactic complete excision of LCMN is ideal, but seldom achievable. Hence, patient education, regular melanoma surveillance, and biopsy of suspicious lesions are very important.
据估计，患有巨大先天性黑素细胞痣（LCMN）的白种人患者患黑色素瘤的终生风险在4.5%至10%之间。目前尚无关于亚洲人群中LCMN与黑色素瘤发生风险的队列研究。
我们试图确定1989年1月至2004年12月期间在新加坡一家皮肤科三级转诊中心就诊的LCMN患者回顾性队列中黑色素瘤发生的风险。
纳入先天性黑素细胞痣（CMN）覆盖至少5%体表面积的患者。数据来自电子记录和照片文档。使用国家癌症登记数据库搜索恶性肿瘤。
共有39例患者（23例男性和16例女性）符合LCMN的研究标准；39例患者中的15例也符合巨大CMN的标准（即预计成年后直径至少为20厘米的CMN）。有29例华裔、6例马来裔、1例印度裔和3例白种人患者。他们的年龄从23个月到60岁不等（平均18.8岁）。他们的平均就诊年龄为26个月，平均随访16.9年。LCMN的大小占体表面积的5%至40%，平均为12.2%。最常见的部位是背部（54%）、下肢（28%）和腹部（26%）。22例患者有卫星病灶。分别对7例头皮/面部或背部有LCMN的患者进行了头部或胸腰椎的磁共振成像检查；所有结果均正常。仅1例患者接受了治疗：他对其LCMN的一小部分进行了二氧化碳激光消融和调Q钕：钇铝石榴石激光治疗。5例出现结节的患者进行了皮肤活检；组织学检查未发现恶性证据。没有患者发生任何形式的恶性肿瘤。
纳入了3例在癌症登记开始前出生的成年患者，这可能导致了生存偏差。样本量较小，无法精确估计我们研究人群中黑色素瘤发生的风险。
在以东南亚人群为主的队列中，LCMN发生黑色素瘤的风险似乎非常低。理想的做法是对LCMN进行预防性完全切除，但很少能够实现。因此，患者教育、定期黑色素瘤监测以及对可疑病变进行活检非常重要。
