An Unusual Case of Hurthle Cell Carcinoma Presenting as Metastatic Pleural Disease 16 Years After Thyroidectomy

Background: Hurthle cell carcinoma (HCC), a variant of a follicular carcinoma of the thyroid, is an aggressive type of differentiated thyroid cancer now considered a distinct pathologic entity. It may present as a low-grade tumor or as a more aggressive type. Prognosis depends on the age of the patient, tumor size, extent of invasion, and initial nodal or distant metastasis. Although thoracic involvement is not unusual with this tumor, this is the first report, to our knowledge, of latent pleural and lung metastases that were detected by a thoracentesis. Patient and Methods: A 63-year-old woman underwent total thyroidectomy for a thyroid mass in 1990 that was diagnosed as HCC. In December 2006, she presented with symptoms of dyspnea and an abnormal chest x-ray. A subsequent ultrasound-guided thoracentesis revealed a malignant, exudative effusion. Cytopathologic analysis revealed the malignancy to be consistent with HCC. She was reevaluated by her original oncologist and is undergoing treatment for metastatic HCC. Conclusions: Although rare, HCC may present years after definitive therapy as metastatic pleural and lung disease. Further studies are needed to determine the cause of latency in such cases.