Cavitary Lung Lesion: An Unusual Presentation of Primary Mediastinal B-cell Lymphoma

Primary mediastinal B-cell lymphoma (PMBL) is a non-Hodgkin B-cell lymphoma that rarely presents as a cavitary pulmonary lesion. We report a 34-year-old man presenting to the ED with shortness of breath, dyspnea, and a cavitary lung lesion seen on chest CT and X-ray. Initial bronchoscopy with fine-needle aspiration and bronchoalveolar lavage did not detect malignant cells, and the patient began empirical antifungal treatment. A repeat bronchoscopy initially arrived at a diffuse large B-cell lymphoma (DLBCL) diagnosis for which the patient started R-CHOP chemotherapy. Subsequent diagnostic assays confirmed a PMBL diagnosis, after which the patient transitioned to DA-R-EPOCH therapy. We discuss the challenges of diagnosing cavitary lymphomas and the value of follow-up testing in improving patient outcomes.