Clinical, molecular and radiological characteristics of thyroid nodules with somatic DICER1 mutations in adults.

BACKGROUND

Information regarding DICER1-related thyroid tumors in children has accumulated; however, the clinical, molecular and radiological characteristics of thyroid nodules with DICER1 mutations in adults are largely unknown, especially those with somatic mutations.

OBJECTIVE

In this study, we sought to find clinical, molecular and radiological characteristics of thyroid diseases with somatic mutations in the DICER1 gene in adults.

PATIENTS

Patients (n = 21) aged ≥18 years with somatic DICER1-related thyroid tumors were enrolled.

DESIGN

From 1,289 patients who underwent genotyping for PTC-associated variants, 21 patients with 23 DICER1-related thyroid tumors and confirmed somatic DICER1 variants were selected and analyzed for clinical, molecular and radiographic features.

RESULTS

Somatic DICER1 variants were found in 21 of 1,289 (1.63%) patients with thyroid nodules in this study. All patients were female predominant. Eleven (11/23) were classified as benign and eight (8/23) were malignant, one was a follicular tumor of uncertain malignant potential (FT-UMP) with suspicious capsular invasion and three were under follow-up, in 23 DICER1-related nodules. Eleven nodules (11/23) had other pathogenic gene mutations (RAS and BRAF), and biallelic DICER1 mutations had a high prevalence, about 34.8% (8/23). Ten nodules (10/20) were combined with other tumors with non-DICER1 mutations. No patients had any local invasion or distant metastasis during follow-up. All DICER1-related nodules lacked unique sonographic features, but had the typical appearance of benign or malignant nodules on ultrasound (US).

CONCLUSION

Somatic DICER1-mutated thyroid nodules in adults usually represent a distinct class of low-risk neoplasms, although they may be accompanied by variants in other thyroid cancer-related genes.