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A B Fig. 1. A 43-year-old man with simple pulmonary eosinophilia. The laboratory findings show peripheral blood eosinophilia (1546/ L) and a positive stool test for clonorchiasis sinensis. Low-dose CT shows ill-defined nodules (arrows) in right lung (A, B). All lesions disappeared on the CT obtained 25 days later. 362
Table 1. CT Findings of Simple Pulmonary Eosinophilia Detected at Low-dose CT Screening for Lung Cancer Lesions Nodule (s) GGO* Nodule (s)+ggo* Patients n=36 18 9 9 * GGO - Ground-glass opacity Fig. 3. A 55-year-old man with simple pulmonary eosinophilia (peripheral blood eosinophil: 795/ L). Low-dose CT shows about a 16mm sized irregular nodule (arrow) in the right upper lobe. The lesion was interpreted as lung cancer, but it disappeared on the follow-up CT obtained 28 days later. A B Fig. 2. A 40-year-old woman with simple pulmonary eosinophilia. Her peripheral blood eosinophil count was 2167/ L. Low-dose CT shows areas of ground-glass opacity without central nodules in both lower lobes (arrows in A and B). The chest CT obtained 30 days later showed negative findings. 363
Table 2. Characteristics of Nodules in Simple Pulmonary Eosinophilia Nodules (n=56) Margin with halo well-defined ill-defined irregular 8 (14) 46 (82) 2 (4) 17 (30) Note.Numbers in parenthesis are percentages. Fig. 4. A 43-year-old man with simple pulmonary eosinophilia (peripheral blood eosinophil count: 772/ L). Low-dose CT shows the ill-defined single nodule with a ground-glass opacity halo (arrow) in the RUL. The lesion resolved completely on the CT obtained 75 days later. 364
Thorax 2004; 59:237-241 6. Diederich S, Wormanns D, Semik M, Thomas M, Lenzen H, Roos N, et al. Screening for early lung cancer with low-dose spiral CT: prevalence in 817 asymptomatic smokers. Radiology 2002; 222:773-781 7. Bain GA, Flower CD. Pulmonary eosinophilia. Eur J Radiol 1996; 23:3-8 8. Holland SM, Gallin JI. Disorders of granulocytes and monocytes. In Kasper DL, Fauci AS, Longo DL, Braunwald E, Hauser SL, 1. Kaneko M, Eguchi K, Ohmatsu H, Kakinuma R, Naruke T, Jameson JL. Harrison s principles of internal medicine, 16th ed., Suemasu K, et al. Peripheral lung cancer: screening and detection New York; MacGraw-Hill, Inc. 2005:349-358 with low-dose spiral CT versus radiography. Radiology 1996; 9. Allen JN, Davis WB. Eosinophilic lung diseases. Am J Respir Crit 201:798-802 Care Med 1994;150:1423-38 2. Sone S, Takashima S, Li F, Yang Z, Honda T, Maruyama Y, et al. 10. Kim Y, Lee KS, Choi DC, Primack, SL, Im JG. The spectrum of Mass screening for lung cancer with mobile spiral computed tomography scanner. Lancet 1998; 351:1242-1245 Tomogr 1997;21:920-930 eosinophilic lung disease: radiologic findings. J Comput Assist 3. Henschke CI, Naidich DP, Yankelevitz DF, McGuinness G, 11. Johkoh T, Muller NL, Akira M, Ichikado K, Suga M, Ando M, et al. McCauley DI, Smith JP, et al. Early lung cancer action project: initial findings on repeat screening. Cancer 2001; 92:153-159 in 111 patients. Radiology 2000; 216:773-780 Eosinophilic lung diseases: diagnostic accuracy of thin-section CT 4. Henschke CI. Early lung cancer action project: overall design and 12. Kim Y, Lee KS, Jung KJ, Han J, Kim JS, Suh JS. Halo sign on high findings from baseline screening. Cancer 2000; 89:2474-24 resolution CT: findings in spectrum of pulmonary diseases with 5. MacRedmond R, Logan PM, Lee M, Kenny D, Foley C, Costello pathologic correlation. J Comput Assist Tomogr 1999; 23: 622-626 RW. Screening for lung cancer using low dose CT scanning. 365
Simple Pulmonary Eosinophilia Detected at Low-dose CT for Lung Cancer Screening 1 Kyung-Nyeo Jeon, M.D., Kyungsoo Bae, M.D., Ho-Cheol Kim, M.D. 2, Duk-Sik Kang, M.D. 3, Jae-Min Cho, M.D., Jae-Wook Ryoo, M.D., Dae-Seob Choi, M.D., Jae-Beom Na, M.D., Jin-Jong You, M.D., Sung-Hoon Chung, M.D. 1 Department of Diagnostic Radiology, Gyeongsang National University Hospital 2 Department of Internal Medicine, Gyeongsang National University Hospital 3 Department of Diagnostic Radiology, Kyungpook National University Hospital Purpose: The aim of this study was to evaluate the frequency, radiologic findings and clinical significance of the simple pulmonary eosinophilia (SPE) that was diagnosed among the asymptomatic patients who underwent low-dose CT scans for the early detection of lung cancer. Materials and Methods: From June 2003 to May 2005, 1,239 asymptomatic patients (1,275 examinations) who visited the health promotion center in our hospital and who underwent low-dose CT were enrolled in this study. SPE was defined as the presence of > 500 eosinophils per microliter of peripheral blood and the presence of abnormal parenchymal lesions such as nodules, airspace consolidation or areas of ground-glass attenuation (GGA) on CT, and there was spontaneous resolution or migration of the lesions on the follow-up examination. We analyzed the CT findings of SPE and we investigated the relationship between the occurrence of SPE and the season, smoking and the presence of parasite infestation. Results: 36 patients were finally diagnosed as having SPE; this was 24% of the 153 patients who were diagnosed with parasite infestation and 2.8% of the total low-dose CT scans. These 36 patients consisted of 31 men and 5 women with a mean age 45.7 years. There was no significant relationship between SPE and the presence of parasite infestation, smoking or gender. Among the patients with peripheral blood eosinophilia, the eosinophil count was significantly higher in the patients with SPE than that in the patients without pulmonary infiltration (p < 0.05). SPE more frequently occurred in winter and spring than in summer and autumn (p < 0.05). The CT findings were single or multiple nodules in 18 patients, nodules and focal GGA in 9 patients and GGA only in 9 patients. Most of the nodules were less than 10 mm (88%, 49/56) in diameter and they showed an ill-defined margin (82%, n = 46); 30% of the nodules (n = 17) showed a halo around them. Conclusion: Simple pulmonary eosinophilia can be suggested as the cause if single or multiple ill-defined nodules or focal GGA are found on the low-dose CT performed in asymptomatic patients with peripheral blood eosinophilia. Short interval follow-up should be recommended to avoid invasive procedures or unnecessary aggressive treatment due to mistaking these lesions as lung cancer or metastatic malignancy. Index words : Lung neoplasms, CT Lung neoplasms, diagnosis Cancer screening Address reprint requests to : Kyungsoo Bae, M.D., Department of Diagnostic Radiology, Gyeongsang National University Hospital 90 Chilam-dong, Jinju 660-702, Korea. Tel. 82-55-750-8211 Fax. 82-55-758-1568 E-mail: ksbae@nongae.gsnu.ac.kr 366