A Korean child with DICER1 syndrome presenting with thyroid manifestations accompanied by other types of neoplasms: case report with a review of literatures.

We experienced a rare case of an 8-year-old girl with a diagnosis of DICER1 syndrome. The patient exhibited renal and thyroid symptoms. On family history, the patient's maternal grandmother and aunt had a diagnosis of multinodular goiter. The patient underwent whole exome sequencing (WES) to examine whether she had cancer predisposition syndrome, including DICER1 syndrome. This showed a heterozygous missense mutation, c.3506C>G (p.S1169*), in exon 21 of the DICER1 gene. Sanger sequencing was performed to confirm the DICER1 variant detected by WES and to examine whether the patient's family members had a mutation in the same DICER1 exon. Two siblings and father of the patient were negative for genetic test, but the patient's mother was positive for DICER1 pathogenic variant. At the age of 16, the patient had a polypoid mass in the right nasal cavity. On histopathology, the patient was found to have nasal chondromesenchymal hamartoma. Our case showed the longitudinal time course of DICER1 syndrome, which has not been described in the Korean literature. In conclusion, our case highlights the importance of thyroid diagnostic work-up; clinicians should consider the possibility of DICER1 syndrome in a child or an adolescent who present with thyroid diseases accompanied by common type of neoplasms.