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Show Journal of Neuro- Ophthalmology 21( 4): 274- 275, 2001. © 2001 Lippincott Williams & Wilkins, Inc., Philadelphia Original Contribution Pneumocystis carinii Granuloma of the Optic Nerve A Histopathologic Case Report David L. Knox, MD, and Wm. Richard Green, MD A 30- year- old man under treatment for acute leukemia died of Candida sepsis and Pneumocystis carinii pneumonia. A small granuloma containing Pneumocystis carinii was found in one optic nerve. Key Words: Pneumocystis carinii- Optic nerve- Granuloma. CASE REPORT A 30- year- old white man with acute lymphocytic leukemia was treated with systemic and local central nervous system chemotherapy by an Ommaya reservoir. His terminal illness featured disseminated Candida tropicalis infection in his liver and spleen as well as Pneumocystis carinii pneumonia. FIG. 1. Left optic nerve, with a 0.5- mm area of inflammation and necrosis ( arrowhead). Hematoxylin and eosin stain, x 25. Manuscript received September 1, 2001; accepted June 1, 2001. From the Wm. R. Green Eye Pathology Laboratory of the Wilmer Eye Institute, Johns Hopkins University School of Medicine and Hospital. Address correspondence and reprint requests to David L. Knox, MD, Eye Pathology Laboratory, Maumenee 427, Johns Hopkins Hospital, 600 N. Wolfe St., Baltimore MD, 21287- 9248; E- mail: daknox @ jhmi. edu FIG. 2. Left optic nerve, detail of area of inflammation shown in Figure 1. Granuloma, with loss of myelin and axons, chronic inflammatory cells and central area of microorganisms. Hematoxylin and eosin stain, x 160. Gross and microscopic examination of both eyes was unremarkable, except for a 0.5- mm lesion of the left optic nerve, which contained macrophages and a 0.1 central area of microorganisms that measured 7 to 8 ( Jim in diameter and had slightly refractile walls ( Figs. 1- 3). DISCUSSION Pneumocystis carinii, an organism of low virulence, is found in the lungs of humans and a variety of animals ( 1). The organism has been classified as a protozoan because of its morphologic features, failure to grow on fungal media, and susceptibility to antiprotozoan drugs. Molecular genetic studies, suggest that P. carinii is more closely related to fungi ( 2). Serologic testing in the first years of life has revealed that many healthy children develop antibodies as evidence of asymptomatic infection ( 3,4). Microorganisms remain dormant until immune deficiency caused by genetic dysfunction, cancer, or immunosuppression from AIDS, or chemotherapy for leukemia or lymphoma allow proliferation in lungs and spread into other organs. 274 PNEUMOCYSTIS CARINII GRANULOMA OF THE OPTIC NERVE 275 FIG. 3. Horseshoe- shaped Pneumocystis carinii. Gomori methe-namine silver stain, x 1360. Ocular involvement by P. carinii has been documented clinically and histopathologically, most commonly in choroid ( 5) and occasionally in conjunctiva, retina, and orbit ( 6). We report the apparent first case of optic nerve involvement by P. carinii. Because there are no clinical details documenting visual acuity or field defect in this patient, we can only speculate that such a lesion would have caused a small peripheral field defect. In a terminally ill patient, it is unlikely that either the patient or his physicians would have noticed such a field defect. Optic nerve should be added to the list of sites of involvement by P. carinii infection and considered as a possible mechanism for an acquired small field defect in an immunodeficient patient. REFERENCES 1. Dutz W. Pneumocystis carinii pneumonia. Pathol Annu 1970; 5: 309- 41. 2. Edman JC, Kovacs JA, Masur H. et al. Ribosomal RNA sequence shows Pneumocystis carinii to be a member of the fungi. Nature 1988; 334: 519- 22. 3. Meuwissen JH, Tauber I, Leeuwenberg AD, et al. Parasitologic and serologic observations of infection with Pneumocystis in humans. J Infect Dis 1977; 136: 43- 9 4. Pifer LL, Hughes WT, Stagno S, Woods D. Pneumocystis carinii infection: evidence for high prevalence in normal and immuno-suppressed children. Pediatrics 1978; 61: 35^ tl. 5. Rao NA, Zimmerman PL, Boyer D, et al. A clinical, histopathologic and electron microscopic study of Pneumocystis carinii choroiditis. Amer J Ophthal 1989; 107: 218- 28. 6. Ruggli GM, Weber R, Messmer EP, et al. Pneumocystis carinii infection of the conjunctiva in a patient with acquired immune deficiency syndrome. Ophthalmology 1997; 104: 1853- 6. J Neuro- Ophthalmol, Vol. 21, No. 4, 2001 |
