[Two cases of intravascular diffuse large B-cell lymphoma diagnosed by transbronchial lung biopsy].

We encountered 2 cases of intravascular diffuse large B-cell lymphoma (IVL) diagnosed by transbronchial lung biopsy (TBLB). The first patient reported fatigue and dyspnea on exertion, but chest radiography and computed tomography (CT) did not reveal any abnormalities. The other patient was referred to our hospital because of incidental findings of abnormalities on her chest radiograph. She felt well, and her physical examination was unremarkable. IVL is a rare type of extranodal lymphoma characterized by the presence of lymphoma cells only in the lumenas of small vessels. Major clinical symptoms such as fever, cough, dyspnea, and loss of body weight are not diagnostic, and chest radiographic findings are also nonspecific. Antemortem diagnosis is relatively difficult, and the prognosis is reported to be relatively poor, but it has been reported that long-term survival may result in patients treated with combination chemotherapy. Therefore, TBLB is a useful procedure for early diagnosis of IVL, and may contribute to good outcome.