Lee SM, et al. Acute fibrinous and organizing pneumonia 157 Figure 1. The chest radiography. The initial chest radiograph reveals diffuse haziness and miliary nodules in both the lungs and slight right pleural effusion. 19.48×108/recipient-kg; mononuclear cells (MNCs), 10.11 ×108/kg; CD34 cells, 1.8×106/kg; and CD3 cells, 21.7× 107/kg. After nonmyeloabrative conditioning with fludarabine (from day -9 to day -5; 25 mg/m2/day1) and melphalan (from day -4 to day -3; 70 mg/m2/day1), the patient underwent allogeneic HSCT with total harvested cells in September 2005. He was treated with cyclosporine A and short-term methotrexate for GVHD prophylaxis. Pulmonary function test (PFT), including spirometry, lung volume, diffusion, and airway resistance, performed before the transplantation showed mild pulmonary insufficiency of the mixed type with decreased cabon monoxide diffusing capacity (DLCO). The patient also had chronic renal failure that was treated with hemodialysis. In November 2005, he complained of cough and dyspnea due to pleural effusion, but the symptoms disappeared after intensified hemodialysis and pleurodesis with talc. In January 2006, he again complained of cough, sputum, and exertional dyspnea for 3 days. On physical examination, the respiratory rate was 18/min and the heart rate was 104 beats/min. However, there was no fever, edema, or cyanosis. Auscultation revealed fine inspiratory crackles in both lung bases. The C-reactive protein level was 6.0 mg/dL (normal: ≤0.4 mg/dL); erythrocyte sedimentation rate, 25 mm/h (normal: ≤9 mm/hours); and serum creatinine level, 4.4 mg/dL (normal: ≤1.20 mg/dL). The white blood cell count was 5200× 103/µL (normal: 4,000-10,000×103/µL) with normal differential counts; hemoglobin concentration, 7.9 g/dL (normal: 14-18 g/dL); and platelet count, 44×103/µL (normal: 150-450×103/µL). Examination of arterial blood Figure 2. HRCT. HRCT scan shows diffuse miliary nodules and ground glass opacity in both the lungs and pleural effusion in the right lobe. Patchy consolidation in the left lower lobe can be noted on the CT scan. gases in room air revealed a pH of 7.527, PaCO2 of 38.8 mmHg, and PaO2 of 72.2 mmHg. Both cytomegalovirus and Pneumocystis carinii were found to be negative by PCR of the bronchoalveolar lavage (BAL) fluid. BAL was also negative for the markers of other infections. Cryptogenic antigen was negative in the peripheral blood. Bone marrow study showed no evidence of leukemic blast. Chromosome analysis showed 46XX, and chimerism analysis revealed complete chimerism. The initial chest radiograph demonstrated diffuse haziness and miliary nodules in both the lungs and slight right pleural effusion (Fig. 1). There were no significant changes on chest radiographs after hemodialysis. High- resolution chest CT (HRCT) scans showed diffuse miliary nodules and ground glass opacity in both the lungs, patchy consolidation in the left lower lobe, and pleural effusion in the right lobe (Fig. 2). He had been on regular dialysis and had not had any change of pleural effusion. PFT findings worsened to extremely severe pulmonary in- sufficiency of a restrictive type and moderately decreased DLCO. At admission day 4, transbronchial lung biopsy was performed. All 6 biopsy specimens revealed similar pathological findings. The specimens showed intra- alveolar spaces containing fibrous plugging with extensive fibrin deposition, a finding consistent with cryptogenic organizing pneumonia with fibrous exudates (Fig. 3A). Fibrin balls with hemosiderin deposition were noted in the alveolar spaces (Fig. 3B). There was no evidence of diffuse alveolar damage, alveolitis, eosinophilic infiltration, or granulomas. Fibrin ball is a characteristic