Rare presentation of metastatic renal cell carcinoma to thyroid gland: A case report

Case report: Thyroid metastasis from hepatocellular carcinoma: a rare case with diffuse solid occupancy and unusual imaging findings

Background

Thyroid metastasis represents a rare occurrence, with commonly observed primary tumors originating from renal cell carcinoma, malignant neoplasms of the gastrointestinal tract, lungs, and breast. However, the metastasis of hepatocellular carcinoma to the thyroid gland remains infrequent. Previous investigations have consistently demonstrated an unfavorable prognosis for patients with malignancies that have metastasized to the thyroid. In this context, we present a noteworthy case of thyroid metastasis from hepatocellular carcinoma (HCC), characterized by a distinct ultrasonographic manifestation of diffuse thyroid lesion, deviating from the previously documented imaging presentations of thyroid metastases in HCC.

Case presentation

A 62-year-old Chinese female patient was diagnosed with hepatocellular liver cancer in 2019, following which she underwent a radical hepatic resection. Pathological examination revealed HCC located in the right lobe (stage T3bN0M0 IIIB). No additional interventions were administered subsequent to the surgery. After a span of 15 months, the patient presented with dyspnea. Ultrasonographic findings showed diffuse solid infiltration within the thyroid gland, along with tumor thrombi in both internal jugular veins. Computed tomography (CT) scans demonstrated malignant thyroid lesions infiltrating the retropharyngeal space, prevertebral space, and esophageal wall. The subsequent pathology report from the puncture biopsy confirmed the malignant nature of the tumor, and immunohistochemical analysis definitively established its hepatic origin.

Conclusions

Patients with a history of HCC should be subjected to long-term monitoring and habitual thyroid ultrasonography. Newly detected thyroid nodules in such patients should be immediately regarded suspect for potential metastatic disease. Even when a nodule doesn't exhibit malignant characteristics on ultrasound, FNAB should be administered promptly to elucidate the pathological condition. Larger, swiftly multiplying thyroid masses should warrant an immediate CNB. The identification of thyroid metastases, particularly when coupled with peripheral tissue invasion, typically signifies a bleak prognosis.

Metastases to the Thyroid Gland: What Can We Do?

Metastases to the thyroid gland arise from other malignant tumors such as renal cell carcinoma, colorectal cancer, lung cancer, and breast cancer. In clinical practice, the incidence is low, and the symptoms are not specific, so it is often missed and misdiagnosed. It is finally diagnosed via the comprehensive application of many diagnostic methods, such as ultrasound, fine-needle aspiration biopsy, and immunohistochemistry analysis. Surgery-based comprehensive treatment is often adopted, but because it is usually in the late stage of the primary tumor, the prognosis is poor. In order to better understand the related characteristics of thyroid metastatic cancer and then improve the clinical diagnosis and treatment and the prognosis of patients, in this paper, we systematically summarize the research status of thyroid metastatic cancer.