Detecting Metastasis of Lung Cancer in Mediastinal Lymph Nodes: The Discrepancy Between Cytology and Histology

Abstract

Dr Okubo and his colleagues reported on the efficacy of stump cytology technique for diagnosing mediastinal lymph node metastasis [1Okubo K. Kato T. Hara A. Yoshimi N. Takeda K. Iwao F. Imprint cytology for detecting metastasis of lung cancer in mediastinal lymph nodes.Ann Thorac Surg. 2004; 78: 1190-1193Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar]. Their conclusion is that imprint cytology for detecting metastasis of lung cancer in mediastinal nodes has high sensitivity and accuracy and is no less useful than a histologic examination. I agree to their opinion that the cytological technique poses comparable diagnostic power. However, the sensitivity of the cytological technique is sometimes too high ie, contaminated cells can be diagnosed as malignant positive [2Carlin B.W. Harrell 2nd, J.H. Fedullo P.F. False-positive transcarinal needle aspirate in the evaluation of bronchogenic carcinoma.Am Rev Respir Dis. 1989; 140: 1800-1802Crossref PubMed Scopus (26) Google Scholar]. Mediastinal lymph node resection is carried out from inside of the pleural space, thus contamination of malignant cells from the pleural space should be considered. In addition, metastasized malignant cells in the lymph duct also may be recognized as lymph node metastasis using cytological techniques. There are many obscure points in their study; status of the malignant effusion and pleural lavage cytology, the status of metastasis to the lymph ducts, and the status of micrometastases using a specific method. In practice, it is very difficult to treat the discrepancy between cytology and histology [3Sawabata N. Matsumura A. Ohota M. et al.Thoracic Surgery Study Group of Osaka UniversityCytologically malignant margins of wedge resected stage I non-small cell lung cancer.Ann Thorac Surg. 2002; 74: 1953-1957Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar]. However, as is the cases of their study, placing the diagnostic priority on cytology may have the potential of excessive diagnosis. ReplyThe Annals of Thoracic SurgeryVol. 81Issue 4PreviewI appreciate the interest shown by Dr Sawabata [1] in our report on imprint cytology for mediastinal node metastasis [2]. In our study, the evaluation of mediastinal node metastasis was not for surgical stump but for staging of lung cancer using the imprint technique. Mediastinal node biopsies were done through the conventional cervical mediastinoscopy in all patients. Therefore no contamination occurs through the pleural space. Pleural effusion, lavage cytology, or micrometastasis in the pleural space never affected the results of mediastinal node metastasis. Full-Text PDF