The lung cancer is one of the most lethal types of cancer. Its incidence has dramatically increased during the last decades. In parallel, imaging has known a great improvement allowing a correct and precise diagnosis in many cases. However, the CT findings can have some misleading appearances making the differentiation between cancer and other pulmonary lesions difficult. Our work aims to discuss the most common differential diagnoses of different aspects of lung cancer and elucidate the limits of CT in its diagnosis.

We conducted a one year retrospective study in the department of radiology at Arrazi hospital at Mohamed VI's university hospital of Marrakech. All patients with tumoral or pseudotumoral lung lesion who underwent a radiological examination (chest X ray + CT) with a histologically confirmed etiology were included.

During this period, we collected 21cases of pseudotumoral pulmonary lesion initially detected on chest x ray then confirmed by CT. The average age of our patients was 55 years old, with male predominance. The clinical presentation was dominated by chronic coughing, dyspnea and hemoptysis. We included 10 cases of different histopathological lung cancer (adenocarcinoma, squamous cells carcinoma, small and large cells carcinoma) and 11 identical lung lesions (silicosis, Ewing sarcoma, tuberculosis, hydatid cyst, lung abscess, endobronchial lipoma and pneumonia. The exact etiology was confirmed by...

Take home messages: Signs of malignancy of the pulmonary nodule: size> 20mm, spiculated contours, air bronchogram, pseudocavitation, eccentric or irregular calcifications [1]. Importance of clinical informations: age, profession. Central masses: it's not always cancer. Pulmonary apex tumors: do not forget that the chest wall can be the starting point [2]. Excavated lung cancer: squamous cell carcinoma ++, centered or eccentric, wall often thick and irregular. Pseudo-tumoral tuberculosis: immunocompetent and immunocompromised, non-specific symptoms and imaging, look at the whole parenchyma, seek associated lesions [3]. Distinction between...

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