Papillary thyroid carcinoma with metastasis to the femur as a rare cause of femoral fracture: A case report

Papillary thyroid cancer (PTC) is the most common form of thyroid cancer However, distant metastases from this cancer are not common. Bone metastases occur in 1-7% of all PTC cases. Femoral metastases from thyroid cancer can lead to serious complications, such as fractures. The present report presents the case of a 53-year-old female patient who was admitted to Nanxishan Hospital (Guilin, China) with left hip pain and a limited range of motion that had persisted for 16 h after a fall. CT and MRI revealed an intertrochanteric fracture of the left femur. Further investigation (thyroid ultrasound scan, thyroid function tests, a lung CT scan and postoperative pathology tests) revealed thyroid cancer with bone metastases, hyperthyroidism and lung metastases. The patient underwent a left femoral head replacement and femoral tumor resection. Postoperative pathological examination confirmed femoral metastasis of PTC (the patient did not undergo any further treatment after surgery and the tumour has not progressed since then). The present case highlights a rare PTC metastasizing to the femur and causing a fracture, suggesting that the possibility of malignant metastasis should be considered in patients presenting with fractures. Furthermore, the present report contributes to deepening the understanding into the metastatic patterns of PTC and highlights the importance of early, aggressive therapeutic intervention in patients with PTC. In conclusion, patients with PTC, especially those presenting with fracture symptoms, should be thoroughly evaluated to rule out the possibility of bone metastasis and appropriate therapeutic measures should be taken in a timely manner.