Combinations of monoclonal antibodies can distinguish primary lung tumors from metastatic lung tumors sampled by fine needle aspiration biopsy.

Transthoracic fine needle aspiration (FNA) biopsies performed under computed tomography (CT) scan (CT-FNA) have greatly improved the cytodiagnosis of lung tumors. However, the distinction between a primary lesion and a metastatic lesion still may be difficult on the basis of morphologic criteria. To evaluate whether a selected panel of monoclonal antibodies (MoAb) to tumor-associated antigens (TAA) can improve the diagnostic potential of FNA, we have immunocytochemically analyzed 122 pulmonary CT-FNA. Whereas conventional cytology was capable of recognizing only the neoplastic nature of the lesions, the immunocytochemical diagnosis could identify the primary or metastatic nature of the pulmonary masses in 92.5% of the cases. The immunocytochemical findings were confirmed by clinical-histopathologic data. The current results demonstrate that the use of immunocytochemical methods can significantly improve the diagnostic accuracy of conventional cytology of lung masses.