Thyroid Gland as a Metastatic Site for Hepatocellular Carcinoma: A Rare Case Report

Abstract

Background: Thyroid gland metastasis from distant primary tumors is uncommon, with liver cancer being a particularly rare source. This case report describes the clinical challenges and diagnostic journey of a thyroid mass in a patient with chronic hepatitis B, liver cirrhosis, and hepatocellular carcinoma, underscoring the rarity and complexity of such metastatic relationships.

Case presentation: A 63-year-old male with a long-standing history of hepatitis B-related liver cirrhosis and a recent diagnosis of hepatocellular carcinoma presented with a rapidly enlarging painful right-sided thyroid mass associated with swelling but no systemic symptoms such as fever or dysphonia. This prompted a thorough diagnostic workup. Enhanced neck scans indicated a mass potentially originating from the thyroid with tracheal compression, yet crucially, there was no evidence of lung involvement based on the chest CT. Despite the rarity of liver-to-thyroid metastasis, the patient's multifaceted medical history warranted a broad differential diagnosis.

Intervention and outcome: Surgical intervention included a right-sided thyroidectomy and partial left thyroidectomy under general anesthesia. Histopathological examination unexpectedly confirmed the presence of metastatic thyroid cancer originating from the primary liver tumor. This led to further extensive surgical management, including lymph node dissection in the central neck area. The postoperative regimen was adapted to include thyroid hormone replacement and ongoing treatment for hepatocellular carcinoma. The patient's postoperative recovery was closely monitored, reflecting stable disease with no immediate complications.

Conclusion: This case highlights the clinical rarity and diagnostic challenges of liver cancer metastasizing to the thyroid. It emphasizes the need for vigilance in patients with known primary malignancies, especially hepatocellular carcinoma, presenting with new thyroid abnormalities. This advocates for a comprehensive diagnostic approach in such atypical presentations.

Keywords: case report; hepatocellular carcinoma; liver cancer; metastatic cancer; thyroid metastasis.

Figure 1

Abdominal CT Scan Showing Hepatocellular Carcinoma. This contrast-enhanced computed tomography (CT) scan of the abdomen demonstrates multiple hypervascular lesions characteristic of hepatocellular carcinoma (HCC) within the liver. The largest lesion is seen occupying the right lobe with significant mass effect and heterogeneous enhancement. The scan provides a clear visualization of the tumor burden and its anatomical relationship with surrounding hepatic structures.

Figure 2

Neck CT Scan Showing Thyroid and Surrounding Structures. This axial slice from a contrast-enhanced computed tomography (CT) scan of the neck displays the thyroid gland with a notable mass in the right lobe. The mass appears as a well-defined area with increased density compared to the surrounding thyroid tissue, suggesting the presence of a neoplastic lesion. No significant or invasion into adjacent structures is visible.

Figure 3

Chest CT Scan Demonstrating Clear Lungs. This axial computed tomography (CT) scan of the chest shows clear lung fields without evidence of nodules, masses, or metastatic disease.

Figure 4

Ultrasound Imaging of the Thyroid Gland. This ultrasound image provides a detailed view of the thyroid gland, highlighting a significant mass in the right lobe. The mass measures approximately 65.7 mm x 38.2 mm. Despite its size, the mass displays well-defined margins and a uniform echotexture, characteristics typically indicative of a benign lesion, rather than a neoplastic origin.

Figure 5

Histopathological Examination of Thyroid Mass. This histopathology slide, stained with hematoxylin and eosin (H&E), shows a high-power microscopic view of the thyroid tissue obtained from the patient. The image demonstrates a dense infiltration of atypical cells with hyperchromatic nuclei and prominent nucleoli, typical features of neoplastic tissue. The irregular arrangement and increased cellular density suggest aggressive tumor behavior, consistent with the histological characteristics of hepatocellular carcinoma metastasis in the thyroid gland. Immunohistochemical staining results further validate the diagnosis: TTF-1(-), Tg(-), Ki-67(10%), HepPar-1(+), Arginase-1(+).