Pathologic Features of Legionnaires' Disease 



down through individual cells under oil immersion or by examining tissue with the electron 

 microscope, 50 or more organisms can be observed in individual macrophages. Many extra- 

 cellular fonns can also be seen. 



We have examined a number of surgical specimens from patients who had serologically 

 confirmed LD. In some, the histologic pattern was identical to that of the acute fibrinopurulent 

 pneumonia previously described for autopsy specimens. In other cases an organizing pneumonia 

 with varying degrees of interstitial fibrosis has been present. We have been unsuccessful in our 

 efforts to demonstrate organisms in these organizing pneumonias using silver impregnation or 

 immunofluorescent staining, and in these cases the diagnosis of LD has been confirmed retro- 

 spectively by seroconversion. Organization may occur late in the course of the disease in an 

 unknown percentage of patients and may result in serious pulmonary functional impairment. 



The pathologic features described here cannot serve as the sole basis for diagnosing LD. 

 However, such histologic patterns in lung tissue certainly indicate the need to rule out or confirm 

 a diagnosis of this disease. A definitive diagnosis of LD must be obtained on the basis of results 

 from the more specific laboratory methods described in other sections of this manual. 



REFERENCES 



L Blackmon, J. A., R.A. Harley, M.D. HickJin, and F.W. Chandler. 1979. Pulmonary sequelae of acute 

 Legionnaires' disease pneumonia. Ann. Intern. Med. 90:552-554. 



2. Blackmon, J. A., M.D. HickJin, F.W. Chandler, and the Special Expert Pathology Panel. 1978. Legion- 

 naires' disease: Pathologic and historical aspects of a "new" disease. Arch. Pathol. Lab. Med. 102: 

 337-343. 



3. Chandler, F.W., M.D. Hicklin, and J. A. Blackmon. 1977. Demonstration of the agent of Legionnaires' 

 disease in tissue. N. Engl. J. Med. 297:1218-1220. 



4. Gimenez, D.F. 1964. Staining rickettsiae in yolk-sac cultures. Stain Technol. 39:135-140. 



5. Luna, L.G. 1968. Manual of Histologic and Special Stairung Technics of the Armed Forces Institute 

 of Pathology, ed. 3. New York, McGraw-Hill Book Co., Inc. 



6. Van Order, A.E., and P.W. Greer. 1977. Modification of the Dieterle spirochete stain. J. Histotechnol. 

 1:51-53. 



7. Winn, W.C, F.L. Glavin, D.P. Perl, J.L. Keller, T.L. Andres, T.M. Brown, CM. Coffin, J.E. Sensecqua, 

 L.N. Roman, and J.E. Craigliead. 1978. The pathology of Legionnaires' disease. Arch. Pathol. Lab. 

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