A 68-year-old nurse presented with new onset of floaters in both eyes in August 2009. She noted her symptoms to be painless without eye redness or discharge. She stated that her symptoms progressively worsened with decreasing visual acuity. She was initially seen by an ophthalmologist 2 months after her symptoms started and was diagnosed with bilateral panuveitis. She denied any trauma or injury to the eye, or having any previous ocular history. Her past medical history was significant for insulin-dependent type 2 diabetes mellitus, hypertension, and hypercholesterolemia. She has a history of being purified protein derivative (PPD) positive with a negative chest X-ray, for which she had never received treatment.
Her visual acuity was initially 20/200 in the right eye and 20/200 in the left eye. Intraocular pressures were within normal range, and her pupils were equally reactive without the presence of a relative afferent pupillary defect. Slit-lamp examination showed 1+ anterior chamber cells in both eyes. Ophthalmoscopic examination of both eyes showed vitreous cells, optic disc edema, small amounts of subretinal hemorrhage, and punctate choroidal lesions throughout the fundus (Figure 1). 
A fluorescein angiogram showed blockage in areas of blood, significant staining in the location of the choroidal lesions without much leakage, and optic nerve hyperfluorescence bilaterally (Figure 2). 
Laboratory investigations revealed a white blood cell count of 11.7 x 109/L. Her erythrocyte sedimentation rate, angiotensin-converting enzyme, liver function test, serum urea and electrolytes, and chest X-ray were normal. Treponema pallidum particle agglutination assay was nonreactive, and Bartonella titers were negative. She was positive for QuantiFERON-TB Gold, but had a negative chest CT scan and normal brain MRI scan.
After consultation with an infectious disease specialist, she was started on prednisone and antituberculosis medications to cover a possible infection given her positive QuantiFERON-TB Gold test result and prior positive PPD test. The patient developed severe nausea after starting her antituberculosis medications and immediately stopped taking these medications. By this time, her vision had decreased to between 6/200 and 20/500 in the right eye but remained 20/200 in the left eye.
Given the need for immunosuppression along with the patient's intolerance to antituberculosis medications, a definitive diagnosis for the cause of her choroiditis was urgently needed. As a result, she underwent a pars plana vitrectomy and chorioretinal biopsy of the right eye to confirm whether the etiology of the patient's multifocal choroiditis was related to a possible extrapulmonary Mycobacterium tuberculosis infection.
The biopsy (0.3 x 0.2 x 0.1 cm) was fixed in 4% formaldehyde and processed entirely in paraffin, and multiple sections were cut and stained with hematoxylin and eosin as well as Brown and Brenn tissue gram stain, Ziehl-Neelsen stain, and Fite's acid-fast stain for mycobacteria, and Grocott's modified Gomori's methenamine silver stain for fungal elements. Microscopic examination revealed a small fragment of uveal tissue expanded by inflammation (Figure 3A) comprised of densely infiltrative, benign-appearing lymphocytes surrounding noncaseating histiocyte clusters (Figure 3B) that are well circumscribed (Figure 3C) and contain occasional multinucleated giant cells (Figure 3D) indicative of granulomatous inflammation. No microorganisms were identified. Unstained biopsy sections were submitted for polymerase chain reaction (PCR) testing in which no AFB DNA was detected with 16S rDNA, rpoB, and hsp65 primer sets, no M. tuberculosis complex DNA was detected with hsp65-amplified probe, no Mycobacterium avium complex DNA was detected with hsp65-amplified probe, and no fungal DNA was detected with 28S rDNA and ITS primer sets. 
Chorioretinal results effectively ruled out an infectious cause for her uveitis. Following this negative biopsy, the patient was diagnosed with ocular sarcoidosis and was started on immunomodulatory therapy for sarcoid-related multifocal choroiditis. She was placed on long-term methotrexate and had resolution of her disc edema, inflammation, and retinal hemorrhages by 1-year follow-up, and stabilization of her chorioretinal lesions. Unfortunately, her visual acuity remained poor given the chronicity of her disease and continued to decline in her right eye secondary to cataract progression.