A Case of Thyroid-Like Follicular Carcinoma of the Kidney

A 51-year-oldwoman with a right renal mass was referredto our hospital. Computedtomographic (CT) scan demonstrated a 30 mm-diameter renal mass with delayed enhancement. She underwent a robotassistedlaparoscopic right partial nephrectomy. The pathological examination showedthat tumor cells with eosinophilic, clear cytoplasm formedtubules of various sizes containing colloid-like material, which resembled the findings of thyroidfollicular carcinoma. The tumor was immunoreactive for vimentin andcytokeratin (CK) 7, whereas it lackedreactivity for thyroidtranscription factor-1 (TTF-1) or thyroglobulin. No tumors were detectedin the thyroidglandor other organs of the patient. Subsequently, the diagnosis of thyroidlike follicular carcinoma of the kidney (TLFCK) was determined. At 4 months postoperatively, the patient is alive with no evidence of disease recurrence. TLFCK is an extremely rare subtype of renal cancer, and only 26 cases have been reportedpreviously. We provide a brief literature review on this cancer.