Metastasis of Mixed Adenoneuroendocrine Carcinoma of the Uterine Cervix to Thyroid Gland

The thyroid metastasis from cervical cancer is extremely rare compared to other organs. It is sometimes difficult to distinguish primary tumors from metastases, as most metastatic thyroid nodules are asymptomatic. In this case, a 54-year-old woman had undergone radical hysterectomy due to cervical tumor of stage IB1 mixed adenoneuroendocrine carcinoma (MANEC) 5 years ago. After 3 years, ultrasound examination revealed a suspicious malignant nodule in the left lobe of thyroid gland at regular postoperative follow-up. This patient had no obvious clinical symptoms. The ultrasonography (US)-guided core needle biopsy (CNB) of the thyroid nodule was performed on the patient. The immunohistochemistry analyses revealed that it was poorly differentiated small-cell neuroendocrine carcinoma (SCNEC). Subsequently, the patient underwent left hemithyroidectomy plus isthmusectomy. The postoperative pathology and immunohistochemistry, combining with clinical history, confirmed that the thyroid nodule was a metastasis from cervical MANEC. Conventional chemotherapy and regular follow-up were carried out after the operation. The patient was readmitted 1 year later for pancreatic metastatic lesions and died 1 month after surgery. Early detection of metastatic cancer is potentially helpful, and when necessary, ultrasound-guided puncture biopsy can be utilized to further diagnose metastatic thyroid cancer.