Alvarez-Mendoza A, Reyes-Esparza J, Ruiz-Maldonado R, Lopez-Corella E, Juarez-Herrera N C
Department of Pathology, National Institute of Pediatrics, Mexico City, Mexico.
Pediatr Dev Pathol. 2001 Jan-Feb;4(1):73-81. doi: 10.1007/s100240010130.
Malignant melanoma (MM) in children, although a rare neoplasm, can occur within a preexisting congenital melanocytic nevus (CMN). All the potential risk factors for this phenomenon are not well known, but increases in S phase and G2 + M phase of cell cycle, DNA aneuploidy, and cell cycle abnormalities in precursor lesions might be among the risk factors. Using paraffin-embedded tissue, we performed a retrospective analysis of DNA content, aneuploidy, and cell cycle by flow cytometry. Two groups of patients were analyzed: 28 children with CMN who did not developed MM, and 6 patients who further developed MM. In this second group, three patients had four biopsies done before the appearance of MM and in two patients biopsies were done after the appearance of MM. All CMN not associated with MM exhibited diploid cells only, their S phase was 11.5% (+/- 3.8), and their G2 + M phase was 2.5% (+/- 2.2). Among those patients who developed MM, 3/6 had an S phase > 15.5 and a G2 + M phase > 2.3 prior to the appearance of MM. Two out of six patients had a tetraploid DNA when MM developed and died with a disseminated MM. They had an S phase > 15.5 and their G2 + M phase was > 2.5. We propose that evaluation of DNA content and cell cycle by flow cytometry is a useful method to supplement biopsy findings in children with CMN who have lesions suspicious of developing a MM.
儿童恶性黑色素瘤（MM）虽属罕见肿瘤，但可发生于先天性黑素细胞痣（CMN）内。该现象的所有潜在危险因素尚不明确，但细胞周期S期和G2+M期增加、DNA非整倍体以及前驱病变中的细胞周期异常可能是危险因素之一。我们利用石蜡包埋组织，通过流式细胞术对DNA含量、非整倍体和细胞周期进行了回顾性分析。分析了两组患者：28例未发生MM的CMN患儿，以及6例进一步发生MM的患者。在第二组中，3例患者在MM出现前进行了4次活检，2例患者在MM出现后进行了活检。所有未合并MM的CMN仅表现为二倍体细胞，其S期为11.5%（±3.8），G2+M期为2.5%（±2.2）。在发生MM的患者中，3/6在MM出现前S期>15.5且G2+M期>2.3。6例患者中有2例在MM发生时为四倍体DNA，并死于播散性MM。他们的S期>15.5，G2+M期>2.5。我们认为，通过流式细胞术评估DNA含量和细胞周期是一种有用的方法，可补充对有MM发生可疑病变的CMN患儿活检结果的评估。
