Patients with non-supernumerary ring chromosome 7 syndrome have an increased incidence of hemangiomas, café-au-lait spots, and melanocytic nevi. The mechanism for the increased incidence of these benign neoplasms is unknown. We present the case of a 22-year-old man with ring chromosome 7 and multiple melanocytic nevi. Two nevi, one on the right ear and the other on the right knee, were biopsied and diagnosed as desmoplastic Spitz nevi. Upon targeted next-generation DNA sequencing, both harbored BRAF fusions. Copy number alterations and fluorescence in situ hybridization (FISH) for BRAF suggested that the fusions arose on the ring chromosome 7. Hence, one reason for increased numbers of nevi in patients with non-supernumerary ring chromosome 7 syndrome may be increased likelihood of BRAF fusions, due to the instability of the ring chromosome.

中文翻译：

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7 号环染色体综合征患者的多发性促纤维性 Spitz 痣伴 BRAF 融合

患有非多生性环状 7 号染色体综合征的患者血管瘤、牛奶咖啡斑和黑素细胞痣的发病率增加。这些良性肿瘤发病率增加的机制尚不清楚。我们介绍了一名患有 7 号环状染色体和多发性黑素细胞痣的 22 岁男性病例。两个痣，一个在右耳，另一个在右膝盖，被活检并诊断为促纤维增生性 Spitz 痣。在靶向下一代 DNA 测序后，两者都含有BRAF融合。BRAF的拷贝数改变和荧光原位杂交 (FISH)表明融合发生在 7 号环状染色体上。因此，非多生环状 7 号染色体综合征患者痣数量增加的一个原因可能是由于环状染色体的不稳定性，BRAF 融合的可能性增加。