Kugar Meredith, Akhavan Arya, Ndem Idorenyin, Ollila David, Googe Paul, Blatt Julie, Wood Jeyhan
Division of Plastic Surgery.
Division of Surgical Oncology.
J Craniofac Surg. 2021 Jun 1;32(4):e342-e345. doi: 10.1097/SCS.0000000000007115.
Giant congenital nevi (GCN), defined as abnormal collections of melanocytes with a diameter greater than 20 cm, occur in 1 in 20,000 births. The lifetime risk of malignant transformation in GCN is reported between 5% and 20% and most commonly occurs in the first 3 to 5 years of life. This article reviews the risk factors of malignant transformation and highlights the diagnostic challenges of malignant melanoma in the pediatric population utilizing a clinical report of a patient with GCN.
A male patient with giant congenital nevus of the scalp with over 20 satellite nevi was evaluated at the authors' institution at 1 week of life. Beginning at 9 months of age, he underwent serial excision of GCN and satellite lesions. Initial pathology showed compound congenital melanocytic nevus. Subsequent pathology on serial excisions demonstrated compound nevus with clonal expansion of pigmented epithelioid melanocytoma (PEM). He then underwent complete excision of GCN. Pathology demonstrated malignant melanoma that was confirmed by consensus review with outside institutions. The patient was diagnosed with stage III metastatic melanoma after further imaging. He was treated with cervical nodal dissection and interferon alpha-2b. At the time of last visit, the patient had no evidence of melanoma.
This case highlights the difficulties of clinical and pathologic diagnosis of malignant melanoma in the setting of GCN. Pathology can vary between biopsy sites and initial biopsies can suggest nonmalignant melanocytic lesions, as demonstrated in this patient's case. Correct histologic evaluation often requires input from a relatively few centers that treat a larger volume of childhood melanoma. Analysis of gene expression profiles aids in accurate diagnosis of PEM, proliferative nodule or melanoma. It is important to differentiate PEM, a low-grade, indolent melanoma, from malignant melanoma as the treatment differs significantly. Review of pathology by expert dermatopathologists from multiple institutions is vital for diagnostic accuracy, and patients with malignant transformation of GCN are best served by multidisciplinary teams.
巨大先天性黑素细胞痣（GCN）定义为直径大于20 cm的黑素细胞异常聚集，在每20000例出生中出现1例。GCN发生恶性转化的终生风险报告为5%至20%，最常发生在生命的前3至5年。本文利用1例GCN患者的临床报告，综述了恶性转化的危险因素，并强调了儿科人群中恶性黑色素瘤的诊断挑战。
一名头皮巨大先天性痣伴20多个卫星痣的男性患者在出生1周时在作者所在机构接受评估。从9个月大开始，他接受了GCN和卫星病灶的系列切除。初始病理显示复合先天性黑素细胞痣。系列切除后的后续病理显示复合痣伴色素性上皮样黑素细胞瘤（PEM）的克隆性扩张。然后他接受了GCN的完整切除。病理显示为恶性黑色素瘤，经外部机构的共识审查得到证实。进一步影像学检查后，该患者被诊断为III期转移性黑色素瘤。他接受了颈部淋巴结清扫和α-2b干扰素治疗。在最后一次就诊时，患者没有黑色素瘤的证据。
本病例突出了在GCN背景下恶性黑色素瘤临床和病理诊断的困难。病理在活检部位之间可能有所不同，初始活检可能提示非恶性黑素细胞病变，本患者的病例即如此。正确的组织学评估通常需要来自相对较少的治疗大量儿童黑色素瘤的中心的意见。基因表达谱分析有助于准确诊断PEM、增殖性结节或黑色素瘤。将低级别、惰性的黑色素瘤PEM与恶性黑色素瘤区分开来很重要，因为治疗方法有很大差异。由多个机构的专家皮肤病理学家进行病理复查对于诊断准确性至关重要，GCN发生恶性转化的患者由多学科团队治疗最为合适。
