Niida et al. Journal of Medical Case Reports 2011, 5:295 http://www.jmedicalcasereports.com/content/5/1/295 Page 3 of 5 Figure 2 18-Fluorodeoxyglucose positron emission tomography images. Sagittal (A) and axial (B) images are shown. Strong tracer uptake appears in the dorsal site of the lung. The standardized uptake value in the lung field is 6.8 (120 minutes after injection). (Figure 3B) and CD79a+ (data not shown). In conclu- sion, FDG-PET-guided TBLB established a histological diagnosis of intravascular lymphoma. Our patient was treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and predonisolone) and achieved complete remission after six cycles (Figure 4). He remains alive and free of recurrent disease 24 months after chemotherapy (sIL-2R 408 U/mL and LDH 159 IU/L). Discussion IVL is an aggressive and systemic disease characterized by massive proliferation of large tumor cells within the lumina of small vessels [1]. Primary pulmonary involve- ment is a very rare condition (approximately 5%) of IVL [2]. The diagnosis of pulmonary IVL is often difficult because of nonspecific clinical and radiographic findings, and several cases have been diagnosed during an autopsy [3,4]. FDG-PET is a noninvasive, three-dimensional, meta- bolic imaging technique that provides higher sensitivity than gallium scintigraphy in common lymphoma [5]. In several previous reports, TBLB was performed in patients with pulmonary IVL at an advanced stage (that is, in patients who had CT abnormalities) [6,7]. But there are only three cases (including our case) in which Figure 3 Immunohistochemical staining. Biopsy specimens of the lung: hematoxylin and eosin (A) and immunoperoxidase (B) stain of CD20. Black arrows show CD20+ lymphocytic infiltration inside the alveolar capillary, a characteristic finding of intravascular lymphoma.