Useful Strategy of Pulmonary Microvascular Cytology in the Early Diagnosis of Intravascular Large B-cell Lymphoma in a Patient with Hypoxemia: A Case Report and Literature Review

Intravascular large B-cell lymphoma (IVLBCL) is a rare extranodal lymphoma characterized by the presence of tumor cells within blood vessels, and it is considered to be a subtype of diffuse large B-cell lymphoma. We report a case of IVLBCL presenting as progressive hypoxemia. In this case, a definitive diagnosis could not be achieved by repeated transbronchial lung biopsy, a bone marrow biopsy, and a random skin biopsy, and the ultimate diagnosis was made on the basis of a pulmonary microvascular cytology (PMC) examination. Therefore, PMC is considered to be a useful strategy for the diagnosis of IVLBCL, particularly in this critically ill patient suffering from hypoxemia.