Abstract

We describe two cases of metastatic Wilms' tumor in the lung with emphasis on the cytologic features of specimens obtained by needle aspiration. One of them was extrarenal Wilms' tumor. The findings were correlated with the histopathologic fea- tures of the primary lesion. Cellular components in the fine needle aspiration cytology (FNAC) slides included blastemal, epithelial, stromal and inflammatory cells with immature tubular differentiation and rosette formation. Recognition of these cellular components in FNAC smears help in establishing FNAC diagnosis of Wilms' tumor. The blastemal cells were represented by small to medium sized cells with scanty cytoplasm having ill-defined borders and round to slightly oval nuclei with evenly dispersed chromatin and small marginated nucleoli. They were seen in our two cases. The differential diagnosis includes neuroblastoma, malignant lymphoma, malignant rhabdoid tumor, clear cell sarcoma, Ewing's sarcoma and embryonal rhabdo-myosarcoma. In conclusion, making a definite cytologic diagnosis of metastatic Wilms' tumor may be possible by light and electron microscopy and immunohi-stochemical staining. The above findings may contribute to the diagnosis of FNAC of metastatic Wilms' tumor.

• Keywords: Wilms' tumor;Metastasis;Lung;Fine needle aspiration cytology;