Pediatric imaging in DICER1 syndrome

Background: DICER1 syndrome, arising from a mutation in the DICER1 gene mapped to chromosome 14q32, is associated with an increased risk of a range of benign and malignant neoplasms.

Objective: To determine the spectrum of abnormalities and imaging characteristics in patients with DICER1 syndrome at a tertiary pediatric hospital.

Materials and methods: This retrospective analysis evaluated imaging in patients ≤18 years with DICER1 germline variants between January 2004 and July 2016. An imaging database search including keywords pleuropulmonary blastoma, cystic nephroma, pineoblastoma, embryonal rhabdomyosarcoma, ovarian sex cord-stromal tumor, ovarian Sertoli-Leydig cell tumor and DICER1 syndrome, was cross-referenced against the institutional Cancer Genetics Program database, excluding patients with negative/unknown DICER1 gene testing.

Results: Sixteen patients were included (12 females; mean age at presentation: 4.2 years, range: 14 days to 17 years), with surveillance imaging encompassing the following modalities: chest X-ray and CT; abdominal, pelvic and neck US; and brain and whole-body MRI. Malignant lesions (68.8% of patients) included pleuropulmonary blastoma (5), pineoblastoma (3), ovarian Sertoli-Leydig cell tumor (1), embryonal rhabdomyosarcoma (1) and renal sarcoma (1); benign lesions (37.5% of patients) included thyroid cysts (2), thyroid nodules (2), cystic nephroma (2), renal cysts (1) and pineal cyst (1). A common lesional appearance observed across modalities and organs was defined as the "cracked windshield" sign.

Conclusion: The spectrum of DICER1-related tumors and the young age at presentation suggest early surveillance of at-risk patients is critical, while minimizing exposure to ionizing radiation.