EDITOR,Sarcoidosis, a multisystem granulomatous disease, involves the eye in approximately 25% to 50% of patients^1 2 and produces numerous ocular findings.³ Definitive diagnosis requires a non-caseating granuloma in the absence of mycobacterial infection on biopsy. Although most patients have abnormal chest x rays, ocular sarcoidosis can precede pulmonary involvement, making diagnosis difficult. The following patient with ocular sarcoidosisunresponsive to corticosteroids and cyclosporinewas diagnosed only after chorioretinal biopsy; she responded to azathioprine therapy.

CASE REPORT
A 32 year old white woman had a 12 year history of granulomatous uveitis in both eyes, resistant to treatment with topical, periocular, and systemic corticosteroids, as well as systemic cyclosporine. The patient presented with intermediate uveitis of the left eye, complicated by cystoid macular oedema, posterior subcapsular cataract, and epiretinal membrane formation. In 1986, she underwent lensectomy, vitrectomy, and membrane peeling with poor visual outcome. Laboratory evaluation, including chest x ray and serum angiotensin converting enzyme level, was normal.

In 1991, she developed active uveitis in the right eye with visual acuity of 20/25; cystoid macular oedema developed, with scattered lesions in the deep retina. The left eye decreased to hand movement. Both eyes showed moderate anterior uveitis, vitritis, and chorioretinal lesions (Fig 1), and a diagnosis of multifocal choroiditis was made.

View larger version (140K): [in this window] [in a new window]   Figure 1   Retinal photograph of the left eye shows substantial vitreous haze. Scattered lesions at the levels of the deep retina and choroid (arrows), as well as mottling of retinal pigment epithelium, are seen in the posterior pole.

Chorioretinal lesions increased in size and number in both eyes, despite cyclosporine, and vision in the right eye worsened to 20/60. She developed peripheral retinal detachment, and a chorioretinal biopsy was performed on the left eye.

Biopsy examination demonstrated a well defined, non-caseating choroidal granuloma (Fig 2), predominantly macrophages surrounded by CD4+ T lymphocytes and a few plasma cells. The retina was gliotic, infiltrated with scattered lymphocytes and plasma cells. Higher expression of Fas, FasL, and Bax, as well as lower expression of Bcl-2 and DNA fragmentation were detected in the granuloma. No micro-organisms were found. Cultures and stains for bacteria, mycobacteria, and fungi were negative. These findings suggest that apoptosis occurs in choroidal granuloma and plays a regulatory role in limiting ocular inflammation.⁴

View larger version (136K): [in this window] [in a new window]   Figure 2   Photomicrograph of a chorioretinal biopsy from the left eye shows a well defined, non-caseating choroidal granuloma predominantly consisting of macrophages and a giant cell (arrow) surrounded by lymphocytes and a few plasma cells. The retina is gliotic, infiltrated with scattered lymphocytes and plasma cells. No micro-organisms were found. (Haematoxylin and eosin; original magnification ×200.)

Upon diagnosis of ocular sarcoidosis and treatment with azathioprine, the patient's vision improved to 20/40 in her right eye and has remained stable for 4 years.

COMMENT
This case illustrates several points: ocular sarcoidosis can occur in the absence of pulmonary signs or symptoms and causes a plethora of ocular findings; the disease eludes accurate diagnosisin this case, a chorioretinal biopsy excluded chronic infection and led to accurate diagnosis⁵; and ocular sarcoidosis can resist corticosteroid therapy. This patient's disease progressed despite treatment with periocular and systemic corticosteroids and cyclosporine, but responded to azathioprine. Azathioprine has been used successfully to treat sight threatening ocular sarcoidosis at 1-1.25 mg/kg/day.⁶ Although sarcoidosis responds to corticosteroids, other immunosuppressive agents may be needed to control ocular disease.