Case presentation
A 69-year-old female patient with a known for years multinodular goiter, presented with a 3-month history of fever up to 38.5oC, night sweating and tenderness in the palpation of the right lobe of the thyroid gland. She also reported fatigue and a 10-kg weight loss over the past 1 month. Fine needle aspiration (FNA) was performed in order to exclude acute thyroiditis, but the cytological picture was compatible with a low-differentiation neoplasm, most likely metastatic adenocarcinoma. The patient was submitted to chest, abdominal and brain computed tomography (CT) scan, a mammography and gastrointestinal endoscopic examination (colonoscopy, gastroscopy), which all revealed no pathological findings. A thyroid scintigraphy with Technetium-99m was also performed, which identified a large multinodular goiter and substernal extension to the right, causing displacement of the trachea. Immediately after, she was taken to the operating theatre where a nodule of hard composition and red-gray coloured surface of about 5 cm in the right lobe of the thyroid and two nodules of the same appearance in the sternohyoid muscle, 2 cm below the hyoid bone, were identified (Figure 1). Total thyroidectomy and resection of the nodules in the sternohyoid muscle were performed and the patient was discharged on the 3rd postoperative day without any complications.
The histological examination revealed unspecified borders of the nodules and areas of high mitotic index, necrosis and hemorrhage. A high-grade neoplasia was confirmed with large epithelioid cells forming solid foci or lining the wall of cystic spaces filled with red blood cells. An infiltrative pattern was observed, albeit without rupture of the thyroid capsule, but with infiltration to the strap muscles, especially in the right sternohyoid muscle. The tumor immunostained for vascular markers (vimentin, CD31 and CD34), whereas epithelial differentiation markers, such as cytokeratins AE1/AE3 were mildly expressed or others, thyreoglobulin and calcitonin, were totally negative. Free surgical margins were detected and no lymph node metastases were recognized.
The diagnosis of thyroid angiosarcoma with extra-thyroid extension to the sternohyoid muscle was established. The patient was subsequently under the oncology surveillance and received 25 sessions of radiotherapy. Chemotherapy with paclitaxel was also suggested, but the patient refused further treatment. She died of the disease 9 months post-surgery.