Bansal Neha, Das Mou, Chatterjee Uttara, Mallick Mamata Guha, Arora Neeraj, Mishra Deepak K
Department of Pathology, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India.
Department of Molecular Genetics, Tata Medical Center, Kolkata, West Bengal, India.
Indian J Pathol Microbiol. 2021 Apr-Jun;64(2):402-405. doi: 10.4103/IJPM.IJPM_38_20.
Pediatric melanomas are uncommon and sometimes arise in the background of giant congenital melanocytic nevus (GCMN). A 1-year-old girl was born with GCMN affecting her left half of the face and smaller nodules affecting trunk, hands, and feet. She developed an ulcerated lesion on the left temporoparietal scalp. The lesion showed features of GCMN along with large nests of a tumor composed of round cells with a vesicular nucleus, prominent nucleolus, plentiful mitoses, and areas of necrosis. Immunostaining for desmin, LCA, CD 20, CD 34, CD 99, BCL-2, and FLI1 was negative. Tumor cells showed immunopositivity for S-100 and HMB-45 confirming the diagnosis of melanoma. Immunostaining for BRAF V600E was negative; however, NRAS mutation was detected on next-generation sequencing. Unlike adult melanomas BRAF mutations are rare but NRAS mutations have been reported in pediatric melanomas. Adjunctive molecular testing will be important to understand the genetic basis of this disease and future targeted therapy.
儿童黑色素瘤并不常见，有时会在巨大先天性黑素细胞痣（GCMN）的背景下出现。一名1岁女孩出生时患有GCMN，累及左半侧面部，躯干、手部和足部有较小的结节。她左侧颞顶头皮出现了一个溃疡病变。该病变显示出GCMN的特征，同时还有由圆形细胞组成的肿瘤大巢，这些细胞具有泡状核、明显的核仁、丰富的有丝分裂以及坏死区域。结蛋白、白细胞共同抗原（LCA）、CD20、CD34、CD99、BCL-2和FLI1的免疫染色均为阴性。肿瘤细胞对S-100和HMB-45呈免疫阳性，确诊为黑色素瘤。BRAF V600E的免疫染色为阴性；然而，下一代测序检测到NRAS突变。与成人黑色素瘤不同，BRAF突变很少见，但NRAS突变在儿童黑色素瘤中已有报道。辅助分子检测对于了解该疾病的遗传基础和未来的靶向治疗将很重要。
