Complete diaphysis resorption of the femur: A case report in a metastatic papillary thyroid cancer

Introduction: Although differentiated thyroid cancers generally have a good prognosis, a small proportion of
patients will have recurrent or progressive disease. Bone resorption due to thyroid cancer can cause significant
challenges in the clinical management and rehabilitation.
Presented case: Nearly total femur resorption was found as a first presentation in a patient with thyroid cancer.
The patient complained about chronic pain in her left thigh that had progressed into an inability to walk. She was
treated by a traditional healer for six years before she was persuaded by a social worker to seek medical help. Xrays
showed pathological loss of the right diaphyseal femur. Neck CT-scan showed a left thyroid mass with
tracheal deviation, with multiple lytic lesions in the sternum and 5th rib. Needle biopsy of the thyroid mass
resulted in an inconclusive follicular neoplasm. Total thyroidectomy and neck dissection revealed a classical type
of papillary thyroid carcinoma. After thyroid ablation, she opted for palliative radiotherapy and bisphosphonate
treatment for the bone metastases.
Discussion: Bone metastases are rarely detected at the time of thyroid cancer diagnosis. In the presence of bone
metastasis, median survival of well-differentiated thyroid cancer decreases into only 4 years. Bone metastases are
often neglected and less studied than regional lymph node and lung metastases.
Conclusion: Although well differentiated thyroid cancer is usually indolent, a neglected bone metastasis at an
initial diagnosis might adversely affect patient’s quality of life and prognosis.