Pediatric Angiosarcoma with Novel Phenotypic and Genotypic Profile in Chinese Children

Introduction: Angiosarcoma is an exceedingly rare entity in pediatric population. Herein, we report two pediatric angiosarcoma with novel phenotypic and genotypic profile. Methods: The two patients' information was summarized by clinical data, histopathology, immunohistochemistry, genetic, treatment, and prognosis. Results: Two Chinese children presented with abdominal mass or consumptive hypothyroidism at 2 and 6 years. A patient presented with a unique histopathology of epithelioid AS with smooth muscle hyperplasia, and carried a novel somatic mutation in FAT1 (c.3929C > T/p. Ser1310Leu) along with germ-line variants in CDK8 (c.895A > C/p. Lys299Gln), FANCI (c.3906-07inv/p. Glu1303Lys), and MST1R (c.3581-83delinsACG/p. Arg1194-Ser1195delinsHisGly). The other patient presented with a novel -clinical phenotype of consumptive hypothyroidism. They received postoperative treatment and were monitored for 20 and 26 months, showing good recovery. Conclusion: The phenotypic and genotypic spectrum of AS in pediatric population was expanded by these two patients, which requires the accumulating more cases to gain a deeper understanding.