Comparative study of cytology and immunocytochemistry with trucut biopsy and immunohistochemistry in diagnosis of localized lung lesions: A prospective study

Percutaneous lung biopsy is now a common procedure in pulmonary medicine, and several different techniques are in use. The most common has been the use of a fine needle under computed tomography (CT) guidance combined with the trucut needle for histology. To evaluate the efficacy of fine needle aspiration cytology (FNAC) and immunocytochemistry in comparison with trucut biopsy and immunohistochemistry in patients with localized intrathoracic lesions suspicious for malignancy. Eighty patients with localized mass lesions in the lung on imaging (chest radiograph/CT) were selected for this study over a period of 1 year. FNAC was carried out by a 22 G spinal needle after localization of the mass in the CT scan followed by guided trucut biopsy. Immunocytochemistry and immunohistochemistry were performed as and when required. The mean age of our study population was 57.6 years and the M:F ratio was 4.2:1. Majority of the lesions were peripheral and in the right lung. Adenocarcinoma was most prevalent (49%), followed by squamous cell carcinoma and small cell carcinoma. Cyto-histopathological concordance was seen in 60 cases (75%). The highest rate of concordance was seen in small cell carcinoma (83.3%). The overall sensitivity of FNAC in distinguishing malignant lung lesions from benign lesions was 84.2% and the specificity was 100%. The sensitivity of cytology in diagnosing small cell carcinoma was 83.3% and of non-small cell carcinoma was 65.38%. Immunocytochemistry was carried out in 34 cases, all of which were followed by immunohistochemistry. Cyto-histopathological concordance was noted in 31 of these cases (91.2%). We used the standard panel of four markers (cytokeratin-7, thyroid transcription factor-1, p63 and CD56) for all selected cases. Cytology along with immunocytochemistry is highly effective in diagnosing and categorizing lung neoplasms, producing comparable results to trucut biopsy and immunohistochemistry.