This are the investigations needed to reach diagnosis in a case of bronchogenic carcinoma , and its differential diagnosis (DDx) . Investigations • X- ray shows : - Coin shadow - Cavity, collapse. - Mediastinum mass - Diaphragmatic paralysis - Effusion - Rib erosion • CT scan chest • Sputum examination (cytology) for malignant cells, this may be helpful in patients who are not fit for bronchoscopy. • Bronchoscopy : biopsy and bronchial brush samples, also it can assess the proximity of central tumours to the main carina. • L. N biopsy from scalene pad of fat . • Mediastinoscopy ( for local extension) • Pleural biopsy in patients with pleural effusion. • If bronchoscopy fails to obtain a cytological diagnosis, percutaneous needle biopsy under CT guidance may be helpful in patients with peripheral tumours. • Laboratory investigations for paramaliganant syndrome .Differential diagnosis of bronchogenic carcinoma Source : Differential diagnosis and investigations of Bronchogenic carcinoma