Intravascular large B-cell lymphoma with FDG accumulation in the lung lacking CT/(67)gallium scintigraphy abnormality

Intravascular large B-cell lymphoma (IVLBCL) is a rare lymphoma characterized by the presence of large tumour cells within the blood vessels. It has been considered that IVLBCL is a highly malignant disease with poor prognosis. However, it has been shown that a therapeutic effect resembling that of conventional B-cell lymphomas may be obtained with the application of systemic chemotherapy at the early stage of this disease. Although involvement in the lung is often detected at autopsy, early diagnosis is quite difficult. In this report, we present a case of IVLBCL with pulmonary involvement where 18-fluoro-deoxyglucose positron emission tomography (FDG-PET) was useful in the early diagnosis. Neither computed tomography (CT) nor (67)gallium scintigraphy could reveal the presence of disease in the lung. Histological evidence of IVLBCL was obtained by TBLB after FDG uptake in the lung was confirmed by FDG-PET. The patient exhibited a good response to the subsequent combination chemotherapy. We propose that FDG-PET is a powerful tool for the early diagnosis of IVLBCL with pulmonary involvement, if the possibility of this disease presents in the patient with respiratory symptoms without abnormal findings by CT and (67)gallium scintigraphy.