What question did this study set out to answer?

To highlight the diagnostic challenges and clinical features of pulmonary intravascular large B-cell lymphoma in a patient misdiagnosed with allergic pneumonia.

March 9, 2026

Pulmonary intravascular large B-cell lymphoma misdiagnosed as allergic pneumonia: a case report and literature review.

Key Result

Transbronchial lung cryobiopsy definitively diagnosed PIVLBCL in patients with diffuse GGOs and isolated DLCO reduction, correcting frequent misdiagnosis as ILD or pneumonia.

Key Points

To highlight the diagnostic challenges and clinical features of pulmonary intravascular large B-cell lymphoma in a patient misdiagnosed with allergic pneumonia.
Detailed patient history and occupational exposure assessment.
Chest CT imaging to identify radiological features such as ground glass opacities.
Transbronchial lung cryobiopsy to confirm diagnosis.
Literature review of previous PIVLBCL cases to establish common presentations.
Patient initially misdiagnosed, but later confirmed PIVLBCL through cryobiopsy.
Chemotherapy led to complete remission and significant improvement in lung function metrics.
Fever and dyspnea were common in 75 reviewed cases, with misdiagnoses frequently noted.

Structured PICO

Population

A 51-year-old female with pulmonary intravascular large B-cell lymphoma (PIVLBCL) initially misdiagnosed as hypersensitivity pneumonitis, and a literature review of 75 PIVLBCL patients.

Intervention

Transbronchial lung cryobiopsy (TBCB) for diagnosis, and R-CHOP chemotherapy for treatment.

Outcome

Diagnostic confirmation and clinical remission.

Clinicians should maintain high suspicion for PIVLBCL when encountering diffuse ground glass opacities with isolated DLCO reduction, where transbronchial lung cryobiopsy can provide definitive diagnosis.

Main Result

Absolute Event Rate: 0% vs 0%

Abstract

Pulmonary intravascular large B-cell lymphoma (PIVLBCL) is an extremely rare subtype of extranodal diffuse large B-cell lymphoma (DLBCL). This hematologic malignancy exhibits nonspecific radiological features, including ground glass opacities (GGOs), often leading to misdiagnosis as interstitial lung disease (ILD). We present a 51-year-old female hairdresser with progressive dyspnea and 20 years of occupational hair dye exposure. Initially, she was misdiagnosed with chronic bronchitis due to a persistent dry cough. Then her initial chest CT demonstrated diffuse bilateral GGOs with isolated diffusion capacity of the lungs for carbon monoxide (DLCO) reduction (46.1% predicted) and normal spirometry, which led to a second misdiagnosis as hypersensitivity pneumonitis (HP). Despite initial improvement with corticosteroids, respiratory deterioration occurred during tapering. Finally, transbronchial lung cryobiopsy (TBCB) confirmed PIVLBCL, showing intravascular lymphoid proliferation (CD20+/BCL-6+/Ki-67≈80%). The R-CHOP chemotherapy treatment led to a complete remission for her, and the DLCO improved to 68% of the predicted value at the 6-month follow-up. A literature review of 75 PIVLBCL patients revealed that fever (74.7%) and dyspnea (65.3%) were the predominant presentations. GGOs were observed in 54.7% of cases, with frequent misdiagnosis as ILD (31.8%) or pneumonia (31.8%). TBCB provided definitive diagnostic evidence, demonstrating its clinical utility in resolving ambiguous pulmonary opacities. Clinicians should maintain high suspicion for PIVLBCL when encountering diffuse GGOs with isolated DLCO reduction, even without classic risk factors.

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