BASALOID-SQUAMOUS CARCINOMA METASTATIC TO RENAL-CELL CARCINOMA - FINE-NEEDLE ASPIRATION CYTOLOGY OF TUMOR-TO-TUMOR METASTASIS

We describe an unusual case of a basaloid squamous-cell carcinoma (BSC C) of the tonsil in a 56-yr-old man that metastasized to a primary ren al-cell carcinoma (RCC) and the lung. The diagnosis of the second prim ary, the RCC, was based an fine-needle aspiration (FNA) cytology. A su bsequent nephrectomy specimen revealed BSCC metastatic to RCC, clear-c ell type. Retrospective analysis of the FNA of the renal mass revealed classic RCC morphology and, in addition, another cytologically distin ctive pattern characterized by occasional sheers of cohesive neoplasti c cells with hyperchromatic nuclei and nuclear molding representative of BSCC. The cytologic features of a subsequent FNA of the lung were c haracteristic of metastatic BSCC. Our retrospective analysis of cytolo gic material from the renal mass underscores the importance of raising the possibility of tumor-to-tumor metastasis when distinctly differen t morphologic features are seen in an otherwise typical cytology of a neoplasm in patients with an already known or suspected second primary . To our knowledge, this case report is the first one documenting meta stasis of BSCC to RCC. (C) 1997 Wiley-Liss, Inc.