The Utility of Fine-Needle Aspiration in the Diagnosis of Primary Lung Tumors and Metastatic Tumors to the Lung, a Retrospective Examination of 1032 Cases
Julia A Adams, Howard H Wu. Indiana University School of Medicine, Indianapolis, IN
Background: With the emergence of improved treatment strategies for patients with malignant lung tumors it has become increasingly more important to adequately diagnose and subclassify lung lesions. In our large retrospective study, we assessed the utility of fine needle aspiration (FNA) in the diagnosis of primary and metastatic tumors to the lung.
Design: We reviewed the archived reports for 1032 patients undergoing FNA of primary lung tumors, metastatic lung tumors, and metastatic tumors to the lung. Based on the diagnoses that were rendered, the cases were grouped into atypical, benign, malignant, nondiagnostic, and suspicious lesions. The malignant FNA cases were further subclassified based on tumor type. Cases with correlating histology were then reviewed and diagnoses compared.
Results: The 1032 FNA cases were grouped as follows; 34 (3.3%) atypical, 142 (13.8%) benign, 717 (69.5%) malignant, 121 (11.7%) nondiagnostic, and 18 (1.7%) suspicious. Subclassification of malignancies diagnosed on FNA were as follows; 297 (41.4%) adenocarcinoma, 159 (22.1%) squamous cell carcinoma, 56 (7.8%) small cell carcinoma, 53 (7.4%) non-small cell carcinoma (NSCLC), 123 (17.2%) metastatic tumors, 15 (2.1%) neuroendocrine carcinoma, and 7 (1%) poorly differentiated carcinoma. Out of all NSCLC cases, 90% were able to be subclassified into either adenocarcinoma or squamous carcinoma on cytomorphology alone or with the help of immunohistochemical stains. Immuno stains were performed on 276 (27%) of the cases. The most frequent origins of metastatic tumors were renal cell carcinoma (22), melanoma (17), colon (15), breast (14), and urothelial carcinoma (10). There was also metastasis from 20 other organs with fewer than 4 cases each. 196 of 335 histologic follow-up specimens were biopsies (transbronchial or transthoracic core). Comparison of the FNA and surgical biopsy showed a sensitivity of 96% for FNA versus 98% for biopsy and a specificity of 100% for both. Sampling error resulted in 8 false negative cases on FNA. The diagnostic rate for FNA was 88.3% (vs 96% for surgical biopsy) and 91.6% of FNAs were able to specifically subtype a malignancy compared to only 80.6% of surgical biopsies.
Conclusions: FNA is comparable to histologic examination in the diagnosis and subclassification of both primary and metastatic lung tumors. 90% of NSCLC cases were able to be further subclassified into adenocarcinoma or squamous cell carcinoma by FNA.
Wednesday, March 21, 2012 1:00 PM
Poster Session VI # 75, Wednesday Afternoon