Orthodeoxia as a presentation of intravascular large B cell lymphoma

Intravascular large B cell lymphoma (IVLBCL) is a rare and aggressive subtype of diffuse large B cell lymphoma, of which clinical presentations are highly variable among geographical areas. A case series of IVLBCL patients from Asian countries reported the disease to be more aggressive and associated with hemophagocytic syndrome than in cases from Western countries. Although published articles recently revealed hypoxemia as a presentation in IVLBCL patients, orthodeoxia has never been documented. A 71‐year‐old man presented with prolonged fever, cough, exertional dyspnoea, and orthodeoxia, later developing hypoxemic respiratory failure and refractory septic shock. Eventually, IVLBCL was diagnosed by random skin biopsy and bone marrow biopsy because of a high index of suspicion. We demonstrated the first case of orthodeoxia as an initial presentation of IVLBCL, clinically compatible with Asian‐variant IVLBCL, which is commonly fatal and diagnostically challenging.