Case report: diagnosis of thyroid cancer by bone marrow biopsy in a patient with lymphoma and goiter.

Metastatic follicular thyroid carcinoma was diagnosed by bone marrow biopsy performed during the staging evaluation in a patient with large-cell lymphoma and diffuse goiter who showed lung and bone lesions upon radiologic examination. After thyroidectomy, both sites concentrated radioactive iodine, confirming their thyroid origin and allowing for the appropriate treatment.