Endobronchial Needle Aspiration in the Diagnosis of Small-Cell Carcinoma: Conclusion
In all five of our patients (Table 1), the forceps biopsy specimens of an endobronchial small-cell carcinoma were nondiagnostic due to either extensive mechanical crush artifact (cases 1, 2, 4, and 5) or to sampling error (case 3). The concurrently obtained cytologic specimens were all nondiagnostic, with the exception of a transtracheal needle aspirate (case 1) and a bronchial wash of borderline adequacy (case 4). The tendency of small-cell carcinoma to undergo crush artifact when sampled by the forceps biopsy technique is well recognized in the surgical pathology literature.” While the presence of crush artifact in an endobronchial forceps biopsy is strongly suggestive of small-cell carcinoma, other entities, such as benign lymphoid infiltrates and lymphoma, may exhibit similar distortion. Hence, a definitive diagnosis of small-cell carcinoma cannot be rendered on crush artifact alone. The propensity of small-cell carcinoma to show crush artifact may be related to a number of factors, including increased cell fragility, scanty cytoplasm, poorly developed desmoplastic response to tumor, altered cellular attachments, and possibly, myofibroblast contraction.Canadian family pharmacy read only The alteration in cellular attachments, as reflected in decreased cellular cohesion, may actually contribute to an increased yield by EBNA sampling. In this regard, Schenk et al have previously noted a significantly higher yield of TBNA in patients with small-cell carcinoma. This finding could not be accounted for solely by the propensity of this neoplasm for bulky mediastinal nodal involvement, and seemed to reflect an increased amenability of this tumor type to diagnosis by this technique.
In a recent survey of bronchoscopy performed in North America, Prakash et al reported that only 12 percent of practicing bronchoscopists routinely use the TBNA procedure. Inexperience with the technique, nonacceptance of specimens by pathologists, and the potential damage to the bronchoscope were cited as reasons for its low use despite the remarkably high yields, safety, and cost savings reported in the literature. Moreover, there is a limit to the number and type of specimens that can be obtained during a routine bronchoscopic procedure. The presence of bulky mediastinal adenopathy or of a paraneoplastic syndrome associated with small-cell carcinoma as well as the more extensive involvement of the bronchial tree (both endobronchial and submucosal) should suggest the possibility of smallcell carcinoma and the need for an EBNA and/or TBNA procedure. Certainly, if the initial bronchoscopic procedure is not definitive and the presence of crush artifact is found in the endobronchial biopsy specimen (as in three of our patients), the use of the EBNA procedure at repeated bronchoscopy may obviate the need for another more invasive and costly diagnostic procedure.
Needle aspiration has proven utility in staging lung cancer and in diagnosing submucosal endobronchial tumors. In addition, our cases suggest that needle aspiration can serve as a valuable diagnostic tool in evaluating exophytic intraluminal lesions, especially when small-cell carcinoma is a diagnostic consideration.