Pediatric Angiosarcoma with Novel Phenotypic and Genotypic Profile in Chinese Children.

Angiosarcoma is an exceedingly rare entity in pediatric population. Herein, we report two pediatric angiosarcoma with novel phenotypic and genotypic profile. The two patients' information was summarized by clinical data, histopathology, immunohistochemistry, genetic, treatment, and prognosis. 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 (c.3929C T/p. Ser1310Leu) along with germ-line variants in (c.895A C/p. Lys299Gln), (c.3906-07inv/p. Glu1303Lys), and (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. 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.