A 50-year-old woman was admitted to our hospital because of pain in her right humerus for 5 years, swelling with limited movement for 4 years in February 2022. Physical Examination: a huge mass with pain could be seen in the right shoulder, which disrupted the normal shoulder. Superficial varicose veins could be seen on the surface of the mass, without swelling or ulcer. The movement of the right shoulder joint was obviously restricted (Figure 1A). Imaging examinations were conducted for the right shoulder of the patient. X-ray, CT and MRI demonstrated a huge soft tissue mass in the upper part of the right humerus, and enlarged lymph nodes in the right supraclavicular fossa, that is, the IV segment of the right lateral neck (Figures 1B-D). In addition, multiple solid nodules in both lungs were found by lung CT (Figures 2A-C). The 18F-FDG PET/CT image also confirmed the above results (Figures 1E,F, 2D). In order to make a definite diagnosis, the patient underwent the needle biopsy for shoulder mass. The pathological result showed that the shoulder mass was a metastatic tumor, possibly originating from thyroid via immunohistochemistry analysis of tissue samples with CK (+), CK7 (+), Ki-67 (10%+), TTF-1(+), TG (+), HPC (-), AFP (-), Syn (-), CgA (-), SATB2 (-), CT (-), p53 (-), NapsinA (-), ER (-), PR (-), CDX2 (-) (Figure 1G).
Then, thyroid examinations were carried out. The serum free thyroxine, TSH, A-TG, A-TPO, PTH and calcitionin were all normal. It was worth noting that the serum thyroglobulin was over 10,000 ng/ml. The thyroid contrast-enhanced ultrasound (CE-US) showed 5.3 mm and 8.4 mm nodules in left and right lobes with TI-RADS 5 (Figures 3A,B). Metastasis was considered to be in the prelaryngeal lymph node (also called Delphian lymph nodes), rather than in lateral cervical lymph nodes by CE-US. The contrast-enhanced CT of thyroid also showed the nodules in thyroid (Figures 3C,D) and enlarged lymph nodes in the right supraclavicular fossa (Figures 3E,F). However, the 18F-FDG PET/CT scan did not find any abnormal glucose metabolism in the thyroid gland and central cervical lymph nodes, but did in the right supraclavicular fossa, which was different from CE-US (Figure 3G). Finally, total thyroidectomy, central cervical lymph node dissection and right lateral cervical lymph node dissection were performed for the patient in March 2022 (Figure 4A). Pathological results show that the nodules in both sides were classical papillary thyroid microcarcinoma (Figure 4B). The BRAF-V600E of the patient was wild-type. Additionally, sutures were found in the cancerous nodule in the right lobe, which came from a partial thyroidectomy for a thyroid benign nodule in 2012 (Figure 4A). Interestingly, the lymph nodes suspected of metastasis by CE-US did not show metastasis, while the lateral lymph nodes showed metastasis.