The Histological Spectrum of DICER1-Associated Neoplasms.

DICER1 syndrome is a heterogeneous cancer predisposition syndrome, characterized by a large variety of benign and malignant tumor types, and caused by germline heterozygous pathogenic variants in the DICER1 gene, which is essential in miRNA processing and RNA interference. The clinical manifestations are diverse, with pleuropulmonary blastoma, Sertoli-Leydig cell tumor, cystic nephroma, uterine cervical embryonal rhabdomyosarcoma, and thyroid follicular nodular disease being the most prevalent tumor types. Since these neoplasms are rare and particularly occur in the pediatric population, pathologists should be aware of the potential relationship of these tumors with an underlying DICER1 syndrome in order to perform or suggest additional molecular pathologic analysis and refer patients and their parents for genetic counseling and testing. This review describes the various DICER1-related tumor types with emphasis on the histological features, reflects on the molecular pathogenesis of DICER1, and aims to raise awareness of this syndrome to facilitate earlier diagnosis.