Epithelioid Angiosarcoma of the Thyroid Associated with Multinodular Goiter, Graves Disease, and Papillary Thyroid Carcinoma

ABSTRACT Objective: We describe an interesting case of primary thyroid epithelioid angiosarcoma associated with both Graves disease and multinodular goiter, presenting as thyrotoxicosis and enlarging neck mass. Methods: Chart review for this single case was approved by the Institutional Review Board and patient consent was obtained. Results: A 61-year-old female with longstanding history of multinodular goiter presented with rapidly enlarging neck girth and symptoms of thyrotoxicosis. Thyroid function testing revealed suppressed thyroid-stimulating hormone (TSH) of <0.005 μIU/mL, an elevated free thyroxine of 3.0 ng/dL (normal range, 0.7 to 1.8 ng/dL), and free triiodothyronine of 5.9 pg/mL (normal range, 1.8 to 4.6 pg/mL). TSH receptor antibodies were significantly elevated. Iodine-123 uptake and scan demonstrated elevated 4- and 24-hour uptake with heterogeneous bilateral distribution, exhibiting background diffuse uptake with a left inferior lobe hypofunctioning nodule, and signal attenuation in the right thyroid lobe due to a right-sided mass visualized subsequently on computed tomography. She required high-dose beta-blockade and methimazole 20 mg 3 times daily with subsequent normalization of thyroid hormones. She underwent thyroidectomy 3 months later. Pathology revealed bilateral multinodular thyroid follicular hyperplasia with an 8-cm epithelioid angiosarcoma in the right lobe with a focal contralateral intrathyroidal intralymphatic metastasis. A separate microscopic focus of papillary thyroid carcinoma (1 mm) in the left lobe was also noted. The patient underwent radiation therapy followed by adjuvant chemotherapy per oncology consultation. Conclusion: Epithelioid angiosarcoma is a rare primary thyroid neoplasm that may present with thyrotoxic state, which was attributed to concomitant diagnosis of Graves disease in our patient. Abbreviations: CT computed tomography; FNA fine needle aspiration; I-123 iodine-123; TSH thyroid-stimulating hormone