A case of malignant lymphoma with a peripheral pulmonary lesion diagnosed by endobronchial ultrasound-guided needle aspiration using a thin convex-probe endobronchial ultrasound bronchoscope.

Background: Performing biopsies of peripheral lesions adjacent to the bronchus is challenging. Conventionally, transbronchial needle aspiration of peripheral pulmonary nodules is performed using a radial echo probe; however, the diagnostic yield remains controversial. More recently, transbronchial needle aspiration of peripheral pulmonary lesions has been attempted using endobronchial ultrasound guidance (EBUS-TBNA); however, reaching the target is often difficult due to limitations in outer diameter and flexibility. Case presentation: A 39-year-old male, previously diagnosed with diffuse large B-cell lymphoma, underwent chemotherapy and achieved complete remission. However, 8 months after the final chemotherapy session, computed tomography revealed a right peripheral lung lesion and lymphadenopathy. Although the lymphadenopathy suggested recurrence of malignant lymphoma, the lesion in the right lower lobe did not appear to have the same pathology. Therefore, EBUS-TBNA was first performed at stations 13L and 4R using a thin convex-probe endobronchial ultrasound bronchoscope. The procedure was also performed on the right peripheral lesion at B10iβy 3 days later. Although obtaining an adequate specimen from station 13L was challenging, all lesions were ultimately diagnosed as malignant lymphoma, and heterogeneity in pathological characteristics was identified. Conclusions: EBUS-TBNA for peripheral pulmonary lesions using a thin convex-probe bronchoscope appears to be an effective diagnostic technique for such lesions.