先天性小痣在恶性黑素瘤发生中的地位

The significance of congenital small nevus in the pathogenesis of malignant melanoma

目前对先天性小痣(CSN)易恶变与否及是否应予预防性切除尚未获共识。本研究应用显微分光光度计DNA定量、N-ras p21蛋白检测、超微结构观察及临床资料分析,对CSN在恶性黑素瘤(MM)发生中的地位进行探讨。结果显示:后天性痣(AN)、CSN、先天性巨痣(CGN)及MM的DNA含量依次递增,各组间有显著差异(P<0.05)。N-ras基因产物p21蛋白检测:26/48例MM阳性,4/13例CGN阳性,2/13例CSN阳性,15例AN全部阴性。电镜下3例CSN、1例CGN皮内痣中找到异常黑素小体。54例MM 6例来源于CSN(11.11％)。结果提示CSN较AN易于恶变,主张作预防性切除,为以往把CGN看作MM“癌前病变”的认识找到了实验依据。

There are controversies concerning whether congential small nevus(CSN)is liable to undergo malignant degeneration and whether it should be resected promptly.The signif-icane of CSN in the pathogenesis of malignant melanoma(MM)was assessed with microspec-trophotometric determination of DNA quantity,the detection of the gene product of N-ras,p21 protein,with ABC technique,ultrastructural study of MM tissue with electron microscopy,and analysis of clinical data of MM.The findings were as follows:(1)The DNA content increased sequentially in order of acquired nevus(AN),CSN,congenital giant nevus(CGN)and MM,and the difference was statistically significant among the 4 groups(P<0.05).(2)p21 protein was expressed in 26/48 of MM,4/13 of CGN,2/13 of CSN and 0/15 of AN.(3)Aberrant melanosomes were found in 15/18 of MM,1/4 of CGN,3/15 of CSN and 0/9 of AN(junctional nevus not included)under electron microscopy.(4)Fifty-four cases of MM were collected after a survey of the clinical materials.Among the 54 cases,6 were originated CSN(11.11%)but none from CGN or AN.These facts suggest that CSN is more liable to undergo malignant degeneration than AN and support the traditional concept that CSN is the precursor of MM.