158 The Korean Journal of Internal Medicine Vol. 24, No. 2, June 2009 A B Figure 3. Microscopic findings of a lung specimen. (A) The biopsied lung shows intra-alveolar spaces containing fibrous plugging with extensive fibrin deposition, a finding consistent with cryptogenic organizing pneumonia with fibrous exudates (H&E, ×100). (B) Fibrin balls with hemosiderin deposition are noted in the alveolar spaces (H&E, ×200). finding of acute fibrinous and organizing pneumonia (AFOP) and presents as dense and red coalescent masses on hematoxylin-eosin (H&E) staining. There were no histological features of uremic lung, including protein-rich edema, vascular congestion, tuberculous infection, or fungal infection. A course of broad-spectrum antibiotics and methylprednisolone pulse therapy (60 mg/day) was administered. At day 28 of the methylprednisolone treatment (30 mg/day), ground opacity and military nodules in both the lungs and right pleural effusion were slightly decreased with concomitant improvement in his respiratory symptoms and O2 saturation. At day 44 of the methylprednisolone treatment, ground glass opacity and miliary nodules in both the lungs increased, and the PFT showed no change. Therefore, we increased the dose of methylprednisolone to 45 mg/day. At day 61 of the methylprednisolone treatment (20 mg/day), the patient developed hemoptysis, for which we performed bronchial angiography with embolization. After 3 days, he died due to respiratory failure. DISCUSSION AFOP was first reported by Beasley in 2002 as an un- usual type of acute lung injury [2]. Progressive dyspnea was the major symptom, with commonly accompanying cough, fever, and chest pain. Thus far, there are only a few reports describing AFOP [2-4]. This disease is charac- terized by histological features comprising prominent intraalveolar fibrin deposition (fibrin balls) and organizing pneumonia [2]. Although its clinical and radiological features have not been precisely defined, AFOP is presumed to be a type of diffuse alveolar damage. It has been reported that AFOP can either be idiopathic or occur in association with a spectrum of clinical conditions, including collagen vascular diseases, adverse drug or chemicals reactions, lymphoma, altered immune status, and inhalation diseases [2,3]. The present patient had a history of acute myeloid leukemia with chronic renal failure. Histologically, there was no evidence of uremic lung, which is char- acterized by generalized protein-rich interstitial and intraalveolar edema associated with the expansion of parenchymal connective tissues and prominent lymphatic duct ectasia [5]. Hemodialysis did not result in the improvement of the lung lesions. These findings indicated AFOP as the histological and clinical diagnosis in this patient. At admission, the HRCT scan revealed new patchy consolidations in the left lower lobe and diffuse military nodules in both the lungs. Accordingly, we suspected miliary tuberculosis or disseminated fungal infection as the diagnosis. These clinical and radiological findings were similar to those described in the case report of Kobayashi [4]. Beasley has described the radiological features of 15 patients with AFOP: the most common radiographic pattern was bilateral basilar infiltration, and nodular lesions were not seen in any of the 15 patients [2]. There appear to be 2 clinical presentations of AFOP. One is the subacute type that resembles COP or bron- chiolitis obliterans organizing pneumonia (BOOP) [6].