Spleen metastasis from thyroid carcinoma. Report of a case with diagnosis by fine needle aspiration cytology

BACKGROUND: Lymphoreticular malignancies are the most common neoplasms involving the spleen. Metastasis can be caused by direct invasion from surrounding tumors or from hematogenous spread. Spleen metastases from thyroid carcinoma are unusual, and only 1 case has been reported; none have been diagnosed by fine needle aspiration cytology (FNAC). CASE: A 75-year-old female was diagnosed 6 months earlier with a poorly differentiated thyroid carcinoma with wide lymphatic and vascular invasion. Abdominal computed tomography (CT) and magnetic resonance imaging showed several spleen nodules. FNAC was performed under CT guidance. Cytologic examination showed atypical epithelial cells with thyroidal characteristics. CONCLUSION: This case had the cytologic findings of a poorly differentiated carcinoma of the thyroid metastatic to spleen. We confirmed the rarity of this pathology and the efficacy of splenic FNAC in the diagnosis.