Rapid ultrastructural examination of FNAs in the diagnosis of intrathoracic tumors.

By coupling radiologic imaging procedures with a fine-needle aspiration (FNA) technique, superficial and deep-seated tumors of the thorax may be sampled for cytopathologic evaluation with relative ease, minimal trauma to the patient, and may avert unnecessary or contraindicated surgery. However, the cytodiagnostic limitations that apply to FNA specimens from other sites also obtain for tumors of the thoracic cavity. Although application of histo- and immunohistochemistry offers some expansion of cytodiagnostic limits, their inherent problems of technical failure and biological capriciousness demand a highly critical if not outright skeptical appraisal of the result when applied to cytology specimens. By extending the basic morphologic principles of cytodiagnosis to include fine structure, its limitations can be largely eliminated. Journals of pathology and specialized atlases contain detailed fine structural descriptions of essentially all recognized neoplasms, and the features that discriminate one neoplasm from another are now well recognized. In most instances, a few well-preserved cells or cell groups obtained from an FNA can provide a morphological diagnosis that rivals or surpasses that of conventional paraffin sections of surgically biopsied material, when evaluated in concert with the cytology preparation.