(1) The importance of standardized pathological diagnosis: The biological behavior of different pathological types of thyroid tumors, ranging from benign thyroid adenomas and junctional thyroid tumors to thyroid cancer, can have a very important impact on patient prognosis and treatment. The status of lymph node metastasis in thyroid cancer is equally important to patient treatment strategies. In order to better assist clinicians in formulating accurate treatment plans and to allow hospitals of different levels and different pathologists to stand on the same platform for patient consultation and treatment, it is important to standardize thyroid histopathological diagnosis.
(2) Preoperative aspiration pathological diagnosis: Preoperative B-ultrasound localized coarse needle aspiration can collect tumor tissues for histopathological diagnosis, which can be clearly diagnosed when the specimen is sufficient and the morphology is typical. Due to the obvious advantage of FNA in thyroid cancer diagnosis, histological aspiration is generally not used as a routine examination, but can be used as a supplementary application in some cases of suspicious and rare types.
(3) Intraoperative frozen pathological diagnosis: The purpose is to characterize the thyroid nodules that have not been diagnosed by preoperative puncture pathology or the pathological diagnosis is unclear, and to clarify the presence or absence of lymph node metastasis in order to decide the operation style of thyroidectomy or the scope of lymph node dissection.
Notes for sending frozen pathology include.
(1) Thyroid: ①Send the specimen to the pathology department as soon as possible after isolation without any fixative. ②If the tumor nodule is <5mm, markings (such as incision or tied sutures) may be considered at the tumor. ③The diagnosis of follicular thyroid tumors, including junctional tumors and follicular carcinoma, requires postoperative observation of the specimen as a whole and adequate sampling to confirm the diagnosis. ④Frozen pathology may not be compatible with paraffin pathology, which needs to be informed to the patient and family as informed consent and signed before surgery or freezing.
(2) Lymph nodes: ①Separately sent for examination to increase the purpose of sending partitions and the accuracy of pathological diagnosis and to avoid missing diagnosis. ②Send the specimen as soon as possible after isolation, keep it fresh, put it into a transparent plastic pouch or specimen box, seal it well, and send it to the pathology department. ③The too-small specimen should not be left outside the body for too long to avoid drying and hardening, resulting in inability to freeze the film or accurate observation under the microscope. ④If sand granules are found in the lymph nodes under the pathology microscope, serial sections should be performed to look for evidence of metastasis or not. (5) It is not uncommon for lymph nodes to be negative for intraoperative freezing and metastatic cancer to appear in deep postoperative paraffin cuts, and the patient and family members need to be informed and signed as informed consent before surgery or freezing.
(4) Postoperative paraffin pathological diagnosis.
(1) Precautions for sampling: (1) make parallel sections every 2-3 mm perpendicular to the long axis of the specimen; (2) examine carefully and pay attention to microscopic carcinoma or nodules; (3) for multiple foci, if malignancy is suspected, each foci should be sampled; (4) for cases suspected of encapsulated vascular infiltrative or microscopic infiltrative follicular carcinoma, all tumor nodule envelopes should be sampled; (5) pay attention to the relationship between the mass and the perithelium; (6) pay attention to the examination of the surrounding thyroid tissue ( band muscle, lymph nodes or parathyroid glands).
(2) Diagnostic guidelines: what should be included in the pathology report: (1) location of the tumor, number and size of lesions; (2) pathological type, subtype, fibrosis and calcification; (3) choroidal and nerve invasion (small nerve invasion near the peritoneum or laryngeal nerve branches); (4) involvement of the thyroid peritoneum; (5) invasion of the strap muscles; (6) presence of other lesions in the surrounding thyroid gland such as chronic lymphocytic thyroiditis, nodular goiter, nodular goiter, and parathyroid gland. (6) other surrounding thyroid lesions such as chronic lymphocytic thyroiditis, nodular goiter, adenoma-like changes, etc.; (7) lymph node metastasis + extraperitoneal invasion of lymph nodes; (8) pTNM staging (AJCC 8th edition); (9) immunohistochemistry as necessary.