case_images: PMC9400018_01
case_images: PET/CT images of the patient. Increased 18F-FDG metabolism showed in (A) the large right humerus (130 x 115 x 174 mm) on the cross, sagittal, and coronal sections and in (B) the left lung (6.5 x 6.0 mm); red arrows indicate the lung lesion.
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case_images: PET/CT with 18F-fluorodeoxyglucose (18F-FDG) showed a large mass in the right humerus (130 x 115 x 174 mm), bilateral lung lesions, and enlarged lymph nodes in the right supraclavicular fossa ( Figure 1 ).
case_images: Histopathological sections of right humerus lesion (magnification, x400). (A) H&E staining and (B-F) Immunohistochemical staining of (B) TTF-1, (C) TG, (D) Ki 67, (E) CK pan, (F) CK 7. TTF-1, TG, CK pan, and CK7 were deeply stained (positive); Ki 67 proliferation index was about 10%.
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case_images: Right humerus lesion biopsy was carried, and the histopathology of the specimen displayed fistular and sieve distribution with obvious nuclear heterogeneity ( Figure 2A ). The immunohistochemical stains were positive for thyroid transcription factor (TTF-1), thyroglobulin (TG), cytokeratin (CK) pan, and CK7 and negative for hepatocyte (HPC), alpha fetoprotein (AFP), Syn, CgA, special AT-rich sequence-binding protein 2 (SATB2), calcitonin, P53, Napsin A, estrogen receptor (ER), progesterone receptor (PR), and cadual type homeobox gene 2 (CDX2), which indicates that the lesion originated from the thyroid follicular epithelial cells and not from the liver, breast, colon, lung, or thyroid parafollicular cells; Ki67 proliferation index was about 10% ( Figures 2B-F ).
case_images: Ultrasound images for the thyroid and cervical lymph node. (A) A hypo-echoic solid nodule with an irregular margin and a taller-than-wide shape (4.7 x 3.7 x 5.3 mm) showed in the upper of left thyroid lobe on the gray-mode ultrasonography. (B) The nodule showed uneven iso-enhancement on the CEUS mode ultrasonography. (C) A swollen lymph node with the absence of fatty hilum (17.4 x 6.6 mm) showed in the right IV compartment of cervical lymph nodes, with no obvious blood flow in the lymph node.
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case_images: IV compartment of cervical lymph nodes ( Figure 3 ). The total thyroidectomy and right lateral cervical lymph node dissection were undertaken; the histopathology confirmed the diagnosis of PTMC with contralateral cervical lymph node metastasis (2/18), indicating two lymph nodes involved in the right IV compartment of cervical lymph nodes, and the total number of the right lateral cervical lymph nodes was 18 ( Figure 4 ). Interestingly, the patients had no central cervical lymph node metastasis (0/7), and the BRAFV600E mutation of the PTMC was wild type.
case_images: Histopathological sections of papillary thyroid microcarcinoma and metastatic lymph nodes. H&E staining of papillary thyroid microcarcinoma in the left thyroid lobe: (A) magnification, x 40; (B) magnification, x 400. Red arrows indicate the PTMC; green dashed circle indicates the amplification part in (B). H&E staining of metastatic lymph nodes: (C) magnification, x16; (D) magnification, x34. Red arrows indicate the metastatic thyroid tissue in the lymph nodes; green arrows indicate the normal part of the metastatic lymph nodes.
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case_images: f4
case_images: IV compartment of cervical lymph nodes ( Figure 3 ). The total thyroidectomy and right lateral cervical lymph node dissection were undertaken; the histopathology confirmed the diagnosis of PTMC with contralateral cervical lymph node metastasis (2/18), indicating two lymph nodes involved in the right IV compartment of cervical lymph nodes, and the total number of the right lateral cervical lymph nodes was 18 ( Figure 4 ). Interestingly, the patients had no central cervical lymph node metastasis (0/7), and the BRAFV600E mutation of the PTMC was wild type.