Systematic thyroid screening in myotonic dystrophy: link between thyroid volume and insulin resistance

• Main Authors: Adrien Ben Hamou, Stéphanie Espiard, Christine Do Cao, Miriam Ladsous, Camille Loyer, Alexandre Moerman, Samuel Boury, Maéva Kyheng, Claire-Marie Dhaenens, Vincent Tiffreau, Pascal Pigny, Gilles Lebuffe, Robert Caiazzo, Sébastien Aubert, Marie Christine Vantyghem
• Format: Article
• Language: English
• Published: BMC 2019-02-01
• Series: Orphanet Journal of Rare Diseases
• Subjects: Myotonic dystrophy; Papillary thyroid carcinoma; Ultrasound scan; Thyroid nodule; Thyroid goiter
• Online Access: http://link.springer.com/article/10.1186/s13023-019-1019-3

Abstract Background Myotonic dystrophy (DM1), a neuromuscular disease related to DMPK gene mutations, is associated to endocrine disorders and cancer. A routine endocrine work-up, including thyroid ultrasound (US), was conducted in 115 genetically-proven DM1 patients in a neuromuscular reference center. The aim of this study was to determine the prevalence and the causes of US thyroid abnormalities in DM1. Results In the whole population (age 45.1 ± 12.2 years, 61.7% female), palpable nodules or goiters were present in 29.2%. The percentage of US goiter (thyroid volume > 18 mL) and US nodules were, respectively, 38.3 and 60.9%. Sixteen of the 115 patients had a thyroidectomy, after 22 fine-needle aspiration cytology guided by thyroid imaging reporting and data system (TIRADS) classification. Six micro- (1/6 pT3) and 3 macro-papillary thyroid carcinoma (PTCs) (2/3 intermediate risk) were diagnosed (7.9% of 115). Thyroid US led to the diagnosis of 4 multifocal and 2 unifocal (including 1 macro-PTC) non-palpable PTCs. Ultrasound thyroid volume was positively correlated to body mass index (BMI) (p = 0.015) and parity (p = 0.036), and was inversely correlated to TSH (p < 0.001) and vitamin D levels (p = 0.023). The BMI, the frequencies of glucose intolerance and PTC were significantly higher in UsGoiter versus non-UsGoiter groups. Conclusion In this systematically screened DM1 cohort, the frequency of UsGoiter, mainly associated to BMI, was about 40%, US nodules 60%, thyroidectomies 13–14%, and PTCs 8%, two-thirds of them being micro-PTCs with good prognosis. Therefore, a systematic screening remains debatable. A targeted US screening in case of clinical abnormality or high BMI seems more appropriate.