S40 Abstracts / Can J Diabetes 41 (2017) S22–S83 112 Co-existing Graves’ Disease with Benign Struma Ovarii: A Case Report LISA D. ALEXANDER, ASHLEY LECKIE, KIRSTEEN BURTON, MICHAEL GEARY, CATHERINE YU Toronto, ON Struma ovarii (SO) is a rare ovarian teratoma containing thyroid tissue that accounts for 1% of ovarian tumors. Thyrotoxicosis is seen in 5% of cases. We present a case of co-existing Graves’ disease with a functioning struma ovarii. A 33 year-old G0 presented with a 3-month history of fatigue and abdominal pain, a recent history of facial sweating, hand tremor, dry eyes, and an unintentional 23 kg weight loss in the past year. On exam, she had brisk reﬂexes, mild proptosis with lid lag and a pelvic mass. Blood work showed an elevated thyroid stimulating hormone-receptor antibody level, thyroid function tests consistent with thyrotoxicosis, and negative gynecologic tumor markers. An MRI pelvis showed large, bilateral adnexal lesions. Whole body uptake and scan showed homogenous thyroid uptake at 2h and 24h of 54% and 77% respectively and increased activity in the right adnexa. Graves’ disease with functioning SO was suspected. She commenced atenolol 25mg PO daily and methimazole 5mg twice daily. She was euthyroid prior to laparoscopic cystectomy. Histology showed benign cystic teratomas with positive immunohistochemical staining for thyroid transcription factor-1. Coexisting Graves’ disease and SO is rare. In previous cases, treatment of Graves’ disease typically preceded the diagnosis of SO by several years, with the SO presenting as persistent thyrotoxicosis following thyroidectomy. Keys to management include ensuring patients are euthyroid prior to surgery to avoid precipitating a thyroid storm, titrating antithyroid medications post-operatively, and completing repeat whole body scintigraphy post-operatively to assess for residual thyroid tissue in the pelvis. 113 Non-ST Elevation Myocardial Infarction with Normal Coronary Arteries as a Presentation of Hypothyroidism SIMONE MENDEL*, TISHA JOY† London, ON Hypothyroidism, despite known effects on cardiac physiology, rarely manifests as an acute myocardial infarction in the setting of normal coronary arteries. Here we report the case of a 43-year-old male who presented as a non-ST elevation myocardial infarction with normal coronary angiography but evidence of decreased left ventricular ejection fraction. During work-up for non-ischemic cardiomyopathy, he was found to have severe hypothyroidism (TSH 356.9 mIU/L [0.27–4.20 mIU/L], free T4 <5.0 pmol/L [10–20 pmol/L], free T3 2.8 pmol/l [2.6–5.7 pmol/L]). He had normalization of his ejection fraction and full resolution of his angina and exertional dyspnea following 3 months of levothyroxine therapy. We discuss the possible mechanisms underlying this presentation and review the differential diagnosis for myocardial infarction in the setting of normal coronary angiography. We conclude that TSH evaluation should be routinely included in the assessment of patients with acute myocardial infarction with normal coronary arteries. 114 Performance of ATA Risk Classiﬁcation in a Single Center Cohort of Pediatric Patients with Differentiated Thyroid Cancer—a Retrospective Study RAAD ALWITHENANI*, SARAH DE BRABANDERE, IRINA RACHINSKY, S. DANIELLE MACNEIL, MAHMOUD BADREDDINE, STAN VAN UUM London, ON Introduction: Differentiated thyroid Cancer (DTC) is the most common endocrine malignancy in children. Retrospective studies show conﬂicting results regarding predictors of persistent and recurrent disease after initial therapy. The ATA recently proposed a clinical classiﬁcation system to identify pediatric thyroid cancer patients at risk for persistent/recurrent disease. Material and Methods: We retrospectively included all patients in our registry diagnosed with DTC at≤18 years of age. We analyzed the prognostic performance of this risk classiﬁcation and other risk factors for predicting response to initial treatment and ﬁnal outcome in pediatric DTC. Results: We included 42 patients, 35 females and 7 males, diagnosed with DTC at a mean (SD) age of 16.1 (1.9) years. Forty-one patients had papillary thyroid cancer, 1 had follicular thyroid cancer. Based on the ATA pediatric risk classiﬁcation, patients were categorized as low (62%), intermediate (9%) or high risk (29%). The median follow-up period was 7.7 (1–41) years. Disease free status was achieved in 81%, 50%, and 33% of the low, intermediate and high risk groups, respectively (P<0.01). At the last visit persistent disease was present in 12%, 25% and 33% (P=0.27). Assessing other risk factors, only the presence of distant metastases resulted in increased presence of persistent disease (P=0.03) Conclusion: This study supports the clinical relevance of the ATA risk classiﬁcation for predicting the response to initial treatment, while no difference was found with respect to disease status at the last visit. This may be due to limited power due t caused by the small number of patients. 115 Evaluation of Patients with Hemithyroidectomy for a Differentiated Thyroid Cancer; is a Limited Surgery Enough? SARAH BÉLAND-BONENFANT, GENEVIÈVE RONDEAU, ANDRÉE BOUCHER, REBECCA LEBOEUF, JEAN-HUGUES BROSSARD, RAPHAËL BÉLANGER, HORTENSIA MIRCESCU Montréal, QC Context: Incidence of thyroid cancer is increasing, mostly because imaging studies are more performant. Most of these cancers do not recur and hemithyroidectomy can be suﬃcient. The aim of our study is to characterize patients who underwent hemithyroidectomy and follow their evolution. Methods: A retrospective study was conducted using the charts of patients who underwent hemithyroidectomy at the CHUM between January 2011 and December 2015. Demographic data, preoperative characteristics and biological and structural parameters following surgery were collected. Results: From the 511 patients with hemithyroidectomy, 185 patients (36%) had a cancer (average age 50 years old). 65% of the cohort had a Bethesda class 3 or 4 (atypia of undetermined signiﬁcance, follicular lesion of undetermined signiﬁcance or follicular neoplasm). Average size of all the cancers was 2.2±1.8 cm, 12% were incidental ﬁndings on the pathology report and papillary cancer was the most frequent (88%). 58% of patients needed a completion thyroidectomy, and 67% of these patients subsequently received a radioactive iodine ablation. At the end of the study, only one patient had a recurrence of his cancer and 3 patients presented an incomplete structural response to treatment. Conclusion: Our study conﬁrms that the patients selected in our center for hemithyroidectomy present a good evolution overall. Additional studies are required to further deﬁne the main factors for selecting patients who would beneﬁt from a limited surgery.