A Case of Struma Carcinoid and Graves Disease

ABSTRACT Objective: We describe a case of co-existing Graves disease and struma carcinoid in a woman with an ovarian mass and history of hyperthyroidism. Methods: Patient history, presentation, diagnostic studies, and treatment are described. Results: A 59-year-old female with an antecedent history of hyperthyroidism was scheduled for resection of a 4.1-cm left ovarian mass. Pre-operative labs demonstrated thyroid-stimulating hormone (TSH) <0.007 μIU/mL, (normal range, 0.500 to 4.500 μIU/mL), free triiodothyronine 3.60 pg/mL (normal range, 2.20 to 3.30 pg/mL), and free thyroxine 1.24 ng/dL (normal range, 0.70 to 1.40 ng/dL). Radioactive iodine uptake (RAIU) was 0% in the neck at both 4 and 24 hours. A functioning strumal tumor was suspected. In preparation for surgery, propranolol 40 mg three times a day was initiated. Pathology of the left ovary was consistent with struma carcinoid. Hyperthryoidism persisted on postoperative follow-up. Repeat RAIU with scan at 6 months postoperative demonstrated 4- and 24-hour uptake in the neck of 10.4% (normal range, 4 to 20%) and 23.6% (normal range, 10 to 30%), with diffuse, minimally inhomogeneous uptake in the thyroid lobes bilaterally and uptake visualized in the pyramidal lobe. There was no uptake outside the neck on whole-body imaging. Thyroid-stimulating immunoglobulin level was 329% (normal range, ≤122%). Taken together, these findings were consistent with Graves disease. The patient was treated with radioactive iodine ablation (16.02 mCi I-131). Six weeks postablation, she developed hypothyroidism (TSH, 28.119 μIU/mL), and levothyroxine was initiated. Conclusion: To our knowledge, this is the first reported case of Graves disease co-existing with struma carcinoid. Graves disease may be diagnosed after resection of strumal tumors in patients with persistent or recurrent hyperthyroidism. Abbreviations: RAIU radioactive iodine uptake T3 triiodothyronine T4 thyroxine TSH thyroid-stimulating hormone