Thyroid cancer is the most common malignant tumor in the endocrine system, mostly seen in women. Microscopic thyroid cancer (TMC) refers to thyroid cancer with the largest diameter of less than 1 cm, mostly papillary carcinoma. There is a rising trend of microscopic thyroid cancer in recent years, and the proportion of microscopic cancer in papillary cancer can be as high as 30% in foreign countries. According to the recent statistics of Air Force General Hospital in 2 years, microscopic thyroid cancer accounts for 44.67% of papillary thyroid cancer. In addition to the disease itself, the increased incidence of microscopic thyroid cancer may also be related to the following factors: (1) Thyroid diseases are gaining more and more attention. Routine physical examinations, especially ultrasound examinations during physical examinations, can detect microscopic cancers that are not clinically detectable, asymptomatic, or even less than 0.5 cm in diameter. (2) Ultrasound-guided fine-needle aspiration biopsy can help detect microscopic thyroid cancer. (3) Other examination methods, such as PETCT examination, for incidental detection of microscopic thyroid masses. Since ultrasound examination is very important for microscopic thyroid cancer, it should be paid special attention. Ultrasound images are characterized by solid hypoechoic nodules with no envelope or incomplete envelope and indistinct or crabfoot-shaped borders. Fine and strong dots are one of the characteristic manifestations of papillary thyroid carcinoma. When gravel-like fine and strong dots are found within the nodule, it is more important to be on high alert, but the dots appearing within the nodule may also be gelatinous nodules, which are not calcifications and need to be carefully differentiated by the ultrasonographer. Ultrasound examination reveals thyroid nodules with longitudinal to transverse ratio greater than 1, high elasticity index score, as well as abundant blood flow in the nodules, all of which may be characteristic of malignant thyroid tumors. Once TMC is detected by ultrasonography, fine needle aspiration cytology (FANC) of the thyroid gland can be performed under ultrasound guidance, which is usually performed under local anesthesia and is less painful. For a single nodule, the diagnosis is confirmed once a positive result is obtained by aspiration. However, for multiple nodules, a puncture result of one nodule does not indicate whether the other nodules have malignant changes. Genetic testing may be useful in the diagnosis of microscopic thyroid cancer, and the most common mutated gene in papillary thyroid cancer is BRAFV600E. Fine needle aspiration combined with mutation gene testing may be useful in the diagnosis of papillary thyroid cancer. The prognosis of those who are positive for this gene mutation is poor, so the preoperative test results can help in the selection of intraoperative surgical approach and prognosis. PETCT can also detect microscopic thyroid cancer by chance. I once treated a patient who underwent whole-body PETCT after kidney cancer surgery and found a large hypermetabolic area in the lower right lobe of the thyroid gland. The mass could not be detected during surgery, and after resection of the right lower pole, the thyroid tissue was cut open, and a small grayish-white nodule the size of a sesame grain was found in the thyroid tissue, which was confirmed to be a micro papillary carcinoma by pathological examination. Since the microscopic thyroid nodule itself is very small, it can be missed with little attention. When a clinician finds a thyroid nodule suspicious of microscopic cancer intraoperatively, a silk marker can be sewn on the attachment of the nodule to remind the pathologist that this area is the focus of examination to avoid missing the diagnosis and to shorten the waiting time for frozen section intraoperatively. In addition, the stitches that have been sewn near the tumor should not be used again to avoid tumor implantation. How to manage microscopic thyroid cancer will be decided according to the size, location, distribution of thyroid tumor, whether there are nodules on the opposite side and whether there are lymph node metastasis. In case of single nodule, lobectomy plus isthmus resection can be performed on the side of the lesion. For bilateral multiple nodules, total thyroidectomy is recommended. For isthmic tumors, bilateral subtotal thyroidectomy with isthmus is indicated. Functional cervical lymph node dissection may be performed in cases of lateral cervical lymph node enlargement. The issue of lymph node dissection in the central region of the thyroid gland for papillary microscopic carcinoma has been discussed more recently. We summarized the lymph node dissection of the central zone in micro papillary thyroid cancer intraoperatively and found that the rate of lymph node metastasis was 41.79%. The most likely complications of central zone lymph node dissection are those of hoarseness due to laryngeal recurrent nerve injury and hypocalcemia due to parathyroid injury. To prevent these two complications, we used intraoperative recurrent laryngeal nerve monitoring and nanocarbon lymphography. The laryngeal nerve monitoring can help prevent laryngeal nerve injury, especially in the presence of laryngeal nerve abnormalities (including laryngeal non-returning nerves). Nano charcoal lymphatic imaging, on the other hand, can both blacken the lymph nodes and guide lymph node dissection, and can also serve as a parathyroid secondary image, i.e., the lymph nodes are blackened and the parathyroid glands are not stained, which helps to identify the lymph nodes and parathyroid glands and prevent inadvertent injury to the parathyroid glands when performing lymph node dissection in the central region. Intraoperative frozen section is helpful in confirming the diagnosis, but sometimes intraoperative frozen section is not definitive, in which case the surgeon should contact the pathologist and inform the pathologist of the intraoperative situation. In such cases, the surgeon should contact the pathologist and inform him/her of the intraoperative situation. After contacting the pathologist, the patient’s family should be informed of the specific procedure to be performed to determine the surgical approach. For those operated for benign thyroid disease, intraoperative frozen section was not performed and postoperative paraffin section reported microscopic thyroid cancer. If glandular lobectomy has been performed, follow-up observation is sufficient. If only partial lobectomy has been performed, the surgical specimen should be examined carefully to check whether there is cancer cell infiltration in the tumor surrounding tissues and whether there is invasion of envelope and blood vessels. If it is confirmed that the tumor has been completely resected, it is not necessary to operate again and can be closely observed and reviewed regularly. To sum up, the diagnosis and treatment of microscopic thyroid cancer is a more complicated issue. The popularity of modern ultrasound examination has discovered microscopic thyroid nodules that are clinically asymptomatic and cannot be detected by clinicians, but is it possible for many patients (or normal people) to have microscopic thyroid cancer? Among the microscopic thyroid nodules detected by ultrasound during routine physical examinations, only a few may be microscopic cancer. It is very difficult for patients themselves, and even for professional clinicians, to identify the possible thyroid cancer among the many medical examiners. Therefore, clinicians should analyze carefully according to the patient’s medical history and examination results. If the diagnosis is difficult to be confirmed at the moment, close observation and follow-up are needed, and the patient should be asked to actively cooperate and review the examination on time to avoid missing the diagnosis.