A 56-year-old male patient arrived at the hospital complaining of dry cough for two months. The patient suffered from dry cough for the past two months prior to his visit to our hospital. The chest computed tomography (CT) scan performed at the local hospital revealed a mass in the right upper lobe of the lung, with right lung hilar and mediastinal lymphadenopathies. The patient had no prior medical history and was a smoker with 30 pack-years. The patient was healthy and have no personal or family history of tumors. The patient presented mild coarse breath sounds in the right upper lung during auscultation. Laboratory tests revealed an increased percentage of neutrophilic leukocytes (78.4%) with normal hematocrit and platelet count values. His CYFRA 21-1 level was 4.03 ng/mL, which was far above the maximum normal limit (3.3 ng/mL). Other tumor markers were all in the normal range. Chest enhanced CT scans revealed a central-type mass in the right lung with enlarged lymph nodes in the right lung hilar, mediastinal and bilateral axillary areas. The CT also displayed thickening of the right bronchial wall. PET-CT showed an increased uptake of 18-fludeoxyglucose in the mass of the right lung hilum and the fear of malignancy was a major concern. This examination also revealed lymph node metastases in the right lung hilar, mediastinal, celiac, right cervical, right supraclavicular and bilateral axillary areas. Flexible bronchoscopy revealed mucosal infiltrative changes at the level of the right upper lobe inlet and the right upper lobe bronchus was obstructed. The other bronchial mucosa was normal. The mucosal endobronchial biopsy at the level of the right upper lobe inlet showed lymphoid hyperplasia. These cells were CD20 positive B-cells and Bcl-2, CD5, CD19, and cyclin D1 were also expressed. This result indicates the possibility of MCL. As the tissue sample of the endobronchial biopsy was insufficient, a mediastinoscopy biopsy of the mediastinal lymph nodes was scheduled. Subcarinal lymph node biopsy was performed under mediastinoscopy. The specimen also showed lymphoid hyperplasia. The immunohistochemical staining showed that these cells were positive for Bcl-2, CD5, CD19, CD20, Cyclin D1 and SOX11 while negative for Bcl-6, CD3, CD10, CD21 and CD23. The percentage of Ki67 positive cells was 25%. Therefore, the diagnosis of MCL was confirmed.