Relapse in lymphoproliferative malignancies is not an exceptional entity and generally occurs within the first 2 or 3 years following the primary treatment. Lymph node biopsy is essential for the diagnosis of relapse and treatment. A 64-years-old woman was referred to our clinic for back pain and dyspnea. Chest X-ray and computed tomography (CT) showed pleural thickening in the right hemithorax and pleural effusion. Hereby, we report a patient with a history of follicular lymphoma treatment 13 years ago, presenting with unilateral pleural effusion and being diagnosed, unpredictably, with relapsing lymphoma by video-assisted thoracoscopic surgery pleural biopsy.