巨大先天性痣恶变伴增生性结节1例并相关文献复习

Malignant Nevus Arising from a Giant Congenital Melanocytic Nevus with Proliferative Nodules:a Case Report and Review of the Literatures

目的探讨巨大先天性痣(giant congenital melanocytic nevi,GCMN)细胞恶变伴增生性结节(proliferative nodules,PNs)的组织病理学特点、分子生物学特征、诊断与鉴别诊断。方法对1例GCMN细胞恶变伴PNs的临床表现、组织病理学特征、免疫组化表达及分子生物学检测结果进行分析并复习相关文献。结果患者为成年女性,自出生起臀部皮肤可见大片灰黑色斑,短期内局部出现大小不等的结节并逐渐融合,表面溃疡形成。组织病理学检查显示,皮内先天性痣(congenital melanocytic neiv,CMN)细胞背景中可见形态较一致的尤文肉瘤细胞样细胞多灶结节状增生,大多数结节内细胞轻度异型,核分裂象1个/mm^(2),为PNs;较大结节内细胞明显异型,胞浆嗜酸,核仁明显,核分裂象4个/mm^(2),有坏死,为CMN恶变。免疫组化检测显示,PNs细胞HMB-45(灶+)、Melan-A(+)、P16(+)、S-100蛋白(+)、D型细胞周期蛋白(CyclinD1)(灶+)、增殖核抗原(Ki-67)(+<5%);恶变细胞HMB-45(-)、P16(+)、Melan-A(+)、S-100蛋白(+),CyclinD1(-)、Ki-67(30%+),基因检测显示BRAF V600E突变。结论GCMN恶变及PNs是罕见的黑色素细胞病变,必须充分取材、全面评估并对PNs及黑色素瘤进行鉴别,避免漏诊、误诊和误治。

Objective To investigate the pathological features,molecular biology characteristics,diagnosis and differential diagnosis of malignant nevus arising from a giant congenital melanocytic nevus(GCMN)with proliferative nodules(PNs).Methods A case of malignant nevus arising from GCMN with PNs in an adult was analyzed in terms of the clinical manifestations,histomorphological,immunohistochemistry and molecular biology characteristics;the related literatures were also reviewed.Results The patient was an adult female with large black patches on the buttocks since birth.In a short period of time,nodules appeared on the patches and gradually increased while ulceration occurred on the surface.Histopathological examination showed that in the background of congenital melanocytic nevi(CMN)cells,multifocal nodular hyperplasia of Ewing’s sarcoma cell-like cells could be seen with consistent morphology.Most nodules were PNs in which cells had mild atypical and mitotic figures of 1 per mm^(2).The greater nodular was melanoma in which cells had severe dysplasia,high nucleus/cytoplasm ratio and mitotic figures of 4 per mm^(2).Necrosis was evident.Immunohistochemistry showed that the cells in PNs were HMB-45(focal+),melan-A(+),P16(+),S-100 protein(+),CyclinD1(focal+)and Ki-67(+<5%),melanoma cell were HMB-45(-),P16(+),Melan-A(+),S-100 protein(+),Cyclin D1(-)and Ki-67(30%+).Molecular detection showed BRAF V600 Emutation.Conclusion Malignant nevus arising from a GCMN and PNs are rare diseases.A comprehensive assessment and differential diagnosis are very important to avoid missed diagnosis,misdiagnosis and mistreatment.