case_images: PMC5663906_01
case_images: Ultrasound appearance of the tumor.
case_images: fendo-08-00257-g001.jpg
case_images: PMC5663906_01_fendo-08-00257-g001.jpg
case_images: F1
case_images: The tumor measured 79 mm x 44 mm x 84 mm and filled the entire left lobe, but was limited to the thyroid without signs of infiltration of the capsule or surrounding tissues (Figure 1).
case_images: Computed-tomography appearance of the tumor.
case_images: fendo-08-00257-g002.jpg
case_images: PMC5663906_01_fendo-08-00257-g002.jpg
case_images: F2
case_images: A contrast-enhanced computed-tomography (CT) of the neck, thorax, and abdomen revealed a mass in the left lobe of the thyroid 58 mm x 58 mm x 60 mm, causing tracheal deviation (Figure 2).
case_images: Histologic examination. Core needle biopsy of the tumor: (A) magnification x200; hematoxylin-eosin staining:small-blue-round-cell tumor; (B) magnification x200; PAS:positive staining; (C) magnification x200; S100:positive staining; (D) magnification x200; CD99:positive staining.
case_images: fendo-08-00257-g003.jpg
case_images: PMC5663906_01_fendo-08-00257-g003.jpg
case_images: F3
case_images: It revealed a small-blue-round-cell tumor with immunophenotype: synaptophysin (+), CD99 (+), PAS (+), CKAE1/AE3 (+), Cam 5.2 (+), TTF1 (-), calcitonin (-), Bcl2 (-), and LCA (-), which suggested a Ewing sarcoma/primitive neuroectodermal tumor (Figure 3).
case_images: Postoperative specimen:left lobe of the thyroid with the isthmus.
case_images: fendo-08-00257-g004.jpg
case_images: PMC5663906_01_fendo-08-00257-g004.jpg
case_images: F4
case_images: Left-sided isthmolobectomy with unilateral cervical lymph node dissection of groups II, III, IV, and V was performed, confirming clinical response to treatment (Figure 4).