Abstract Introduction Peripheral T-cell lymphomas (PTCL) are a group of aggressive non-Hodgkin lymphomas derived from mature T cells, accounting for approximately 10-15% of all non-Hodgkin lymphoma cases 1. Among these, nodal T follicular helper (TFH) cell lymphomas represent a recently recognized subtype characterized by neoplastic proliferation of CD4+ T cells expressing markers such as CD10, BCL6, and PD-1. Here, we present a rare case of nodal T follicular helper T-cell lymphoma with bilateral pleural effusions and pulmonary involvement, initially masquerading as severe pneumonia and respiratory failure. This report emphasizes the importance of considering lymphomatous infiltration in the differential diagnosis of unexplained pleural effusions or respiratory compromise in patients with known T-cell lymphoma. Case A 46-year-old man presented to the emergency department with a two-day history of fever, chills, congestion, and worsening dyspnea. Six weeks earlier, he received a left cervical lymph node core biopsy that revealed atypical T-cells positive for CD10 with scattered EBV-positive cells, suspicious for nodal T follicular helper T-cell lymphoma. A computed tomography angiography (CTA) of the chest ruled out pulmonary embolism but demonstrated extensive supraclavicular, mediastinal, hilar, and axillary lymphadenopathy consistent with known lymphoma, as well as a large bilateral pleural effusion with complete right middle and lower lobe collapse and diffuse interstitial pulmonary edema (Figure 1). Due to worsening hypoxia and hypotension, he was transferred to the medical intensive care unit (MICU) and was subsequently intubated, started on pressors, and given broad-spectrum antibiotics. He received bilateral chest tubes, and pleural fluid analysis was negative for culture growth. However, flow cytometry on his pleural fluid showed atypical lymphocytes positive for CD4 and CD10, indicative of T-cell lymphoma. Oncology was consulted, and he was started on cyclophosphamide, doxorubicin, vincristine, and prednisone. He was eventually stabilized and discharged with close oncologic follow-up. Discussion Peripheral T-cell lymphoma commonly presents with extranodal involvement, mostly affecting the skin, gastrointestinal tract, liver, and bone marrow. Pulmonary and pleural involvement, while uncommon, are clinically significant manifestation of T-cell lymphomas. As in this case, pulmonary findings can include interstitial infiltrates, nodules, or pleural effusions, which can mimic infectious and inflammatory processes and lead to delayed diagnosis. Thus, it is important to perform flow cytometry and immunophenotyping of pleural fluid as these are essential tools to distinguish malignant pleural effusions from other benign causes. This can also expedite a completely alternate treatment course for the patient, as early initiation of systemic chemotherapy can significantly improve patient outcomes. This abstract is funded by: None
Lee et al. (Fri,) studied this question.