Niida et al. Journal of Medical Case Reports 2011, 5:295 http://www.jmedicalcasereports.com/content/5/1/295 Page 4 of 5 Figure 4 18-Fluorodeoxyglucose positron emission tomography images after chemotherapy. Sagittal (A) and axial (B) images are shown. Tracer uptake is not seen in the lung field six months after chemotherapy. FDG-PET has proven useful in selecting a biopsy site for the early diagnosis of pulmonary IVL without a CT abnormality [8,9]. FDG accumulation is seen in other diffuse lung diseases such as tuberculosis, sarcoidosis, and interstitial lung diseases [10], but, owing to the rar- ity of pulmonary IVL, a specific pattern of tracer uptake in this disease is not well known. In our case, the pul- monary FDG uptake was diffuse, but strong accumula- tion was seen in the lower dorsal lung field. This accumulation pattern might reflect the gravitational effect in pulmonary circulation because distribution of pulmonary blood flow is highest in the lower lung field, “zone 3 of pulmonary circulation” [11]. IVL is a diffuse lymphoproliferative disease within small vessels; there- fore, strong FDG accumulation in the lower lung field may suggest the presence of many tumor cells spreading hematogenously within pulmonary capillary vessels. The median overall survival of IVL is 10 months, even after chemotherapy [12]. However, systemic chemother- apy at an early stage might improve the long-term prog- nosis of patients with IVL [13,14]. Our patient is rare in that he has pulmonary IVL and remains in complete remission more than 24 months after chemotherapy. This favorable long-term prognosis may reflect the advantage of FDG-PET, which can detect early lesions of pulmonary IVL with no CT abnormality. Conclusions To the best of our knowledge, this is the first report of a long-term (24 months) survivor of pulmonary IVL diagnosed by TBLB according to FDG-PET findings. We propose that FDG-PET is a useful guide for TBLB in the early diagnosis of pulmonary intravascular lym- phoma, especially in patients who have no CT abnormality. Consent Written informed consent was obtained from the patient for publication of this case report and any accompany- ing images. A copy of the written consent is available for review by the Editor-in-Chief of this journal. Abbreviations CT: computed tomography; FDG: 18-fluorodeoxyglucose; FDG-PET: 18- fluorodeoxyglucose positron emission tomography; HRCT: high-resolution computed tomography; IVL: intravascular lymphoma; LDH: lactate dehydrogenase; R-CHOP: rituximab, cyclophosphamide, doxorubicin, vincristine, and predonisolone; sIL-2R: soluble interleukin-2 receptor; TBLB: transbronchial lung biopsy. Author details 1Division of Cardiovascular Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan. 2Division of Pulmonary Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan. 3Division of Hematology, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan. 4Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan. 5Regional Resources Division, Shizuoka Cancer Center Research Institute, 1007 Shimonagakubo, Nagaizumi-cho, Sunto-gun, Shizuoka 411-8777, Japan. Authors’ contributions TN analyzed and interpreted the patient’s data and made the initial diagnosis of intravascular lymphoma. KI and KM performed echocardiography and contributed to writing the manuscript. SK performed transbronchial lung biopsy with the assistance of HK, who interpreted the histological findings regarding intravascular lymphoma. AK and FK performed chemotherapy. KH interpreted the patient’s radiological findings. MK supervised the clinical examination. FO performed the literature review and was responsible for writing the manuscript. All authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Received: 3 August 2010 Accepted: 7 July 2011 Published: 7 July 2011 References 1. Gatter KC, Warnke RA: Intravascular large B-cell lymphoma. In World Health Organization: Pathology and Genetics of Tumors of Heamatopoietic