Diagnosis of pulmonary blastoma by fine-needle aspiration biopsy: cytologic and immunocytochemical findings.

A preoperative diagnosis of pulmonary blastoma was established by fine-needle aspiration (FNA) cytology in a patient who presented with a pulmonary mass discovered incidentally on chest x-ray. At the time of computed tomography-guided FNA, an on-site preliminary diagnosis of poorly differentiated carcinoma was made after examination of a rapid hematoxylineosin (H&E)-stained smear. Malignant epithelial and stromal elements could be demonstrated on smears subsequently stained with the H&E, Papanicolaou, and Diff-Quik methods. The cell block preparation showed a distinctly biphasic malignant tumor with classic morphologic features of pulmonary blastoma. We present the clinical, cytologic, immunocytochemical, and histologic findings of this case and re-emphasize the valuable contribution of adequate cell block preparations to accurate diagnosis of fine-needle aspiration material.