Primary Pleural Lymphoma in an Immune-Competent Patient: A Diagnostic and Therapeutic Challenge

<b>Background:</b> Primary pleural lymphoma is a rare disease posing diagnostic and therapeutic challenges. <b>Case presentation:</b> We present a 65-year-old woman with dyspnoea, cough, and asthenia, with no significant past medical history. Chest X-ray and computed tomography showed extensive right pleural effusion. Video-assisted thoracoscopy demonstrated multiple pleural nodules, while pleural fluid analysis revealed a lymphocytic exudate, and finally, a primary pleural lymphoma diagnosis was confirmed by immunohistochemistry analysis in pleural nodules biopsy. <b>Discussion:</b> In this regard, eight cycles of chemotherapy with cyclophosphamide, doxorubicin, vincristine, dexamethasone, and rituximab were indicated, and after one year of follow-up, complete clinical and radiological remission was observed. <b>Conlusions:</b> We conclude that video-assisted thoracoscopy with an appropriate histopathological examination remains the gold standard for diagnosis, while R-CHOP chemotherapy plus rituximab may represent a highly effective therapeutic choice.