MON-093 Pleuropulmonary Blastoma and Multinodular Goiter in a 22 Yr Old Male with DICER1 Syndrome

Background DICER1 syndrome is an autosomal dominant condition due to mutations in the DICER1 gene, located on chromosome 14q32.13. Patients are at increased risk for malignant and benign tumors, including pleuropulmonary blastoma (PPB), cystic nephroma, ovarian Sertoli-Leydig cell tumors, multinodular goiter (MNG) and differentiated thyroid cancer (DTC). MNG is very common in patients with DICER1 Syndrome but data on incidence is lacking. MNG is more common in females than males. Case presentation: 22 year old man who originally presented with pleuropulmonary blastoma, Type 3 at 3 years of age. His treatment included pulmonectomy, radiation of 46.6 Gy to thorax, and alkylating agents including Cisplatin, Ifosphamide and Cytoxan. He developed frontal lobe metastasis over the course of 3 years and was treated with focal cranial radiation. His father and maternal uncle had history of lung cancer. He was evaluated at the Endocrine clinic at 12 years 10 months for short stature. His height was 132.5 cm (SDS -2.96), weight 29.7 kg (SDS -2.40), and BMI 16.99kg/m² (SDS -0.61). On examination he had normal thyroid exam and Tanner 2 bilateral 4 cc testicles. He was treated with Levothyroxine for subclinical hypothyroidism (TSH: 5.96 uIU/ml (0.35–5.5) and Free T 4: 0.99 ng/dl (0.8–1.80) and growth hormone (GH) for growth hormone deficiency (peak GH was 7.7 ng/ml after Arginine and Clonidine GH stimulation test). At 14 years 10 month he developed respiratory distress. CT scan of chest showed right lower pole nodule 1.6 x 1.5 x 1.4 cm. Ultrasound of thyroid showed right thyroid solid mid pole isoechoic nodule 1.4 x 1.7 x 1.3 cm with multiple enlarged bilateral cervical nodes, largest left supraclavicular region > 1 cm. Biopsy of the right nodule was negative for malignancy. Over the course of 2 years he developed new right thyroid isoechoic nodule in the lower pole 2.1 x 2.5 x 1.9 cm and new left thyroid isoechoic nodule in the upper pole 1.0 x 0.5 x 0.5 cm. Biopsy was negative for malignancy. Due to his PPB, MNG and family history of lung cancer he was evaluated at our genetic cancer clinic and tested positive for germline DICER1 pathogenic variant c.4605_4606del (p.Cys1535Trpfs*3) Conclusion: Our 22 year old male presented with pleuropulmonary blastoma and over the course of few years developed MNG. Genetic testing was positive for germline DICER1 pathogenic variant c.4605_4606del (p.Cys1535Trpfs*3). Our case illustrates the importance of consideration of: 1) Testing children with PPB for DICER1 Syndrome as there are screening recommendations including regular thyroid ultrasound and examinations to look for MNG or other features concerning for thyroid gland neoplasia. 2) MNG is uncommon in children and detection of this should raise suspicion for consideration of testing for DICER1 Syndrome.