Intravascular Large B-Cell Lymphoma Presenting with Hypoxemia without any Abnormalities on Standard Imaging Studies.

BACKGROUND Intravascular large B-cell lymphoma (IVLBCL) is characteristically diagnosed by histological examination of biopsies of bone marrow or randomly harvested skin specimens in the absence of any diagnostic abnormalities on imaging studies, including computed tomography (CT). In particular, diagnosis of IVLBCL with pulmonary manifestations is challenging, because even in patients with severe respiratory failure, there are rarely abnormalities on standard imaging studies. CASE REPORT A 75-year-old female presented with fatigue, weight loss, and high fever with chills for 3 months. Blood examinations on her initial visit to her primary physician showed high concentrations of C-reactive protein, lactate dehydrogenase, and soluble interleukin-2 receptor. There were no abnormalities on imaging studies. She was subsequently admitted to our hospital because of development of dyspnea over time (4 months after symptom onset). Although she was suspected of having IVLBCL, repeated biopsies from bone marrow, skin, liver, and lung did not result in a diagnosis. Finally, a lung biopsy obtained by video-associated thoracic surgery (VATS) from the right lung base, where fluorine-18 fluorodeoxyglucose positron emission tomography had shown high uptake, resulted in a definite diagnosis of IVLBCL. CONCLUSIONS Highly invasive procedures such as thoracoscopic lung resection may be required to diagnose IVLBCL with pulmonary manifestations which can cause severe respiratory failure in the absence of any abnormalities on standard imaging studies.