A 60-year-old Caucasian male presented to the Department of Ophthalmology in Poznan with a complaint of bilateral ocular redness, pain, severe photophobia, and progressive deterioration of vision in April 2015. Three months earlier, he had been diagnosed with bilateral conjunctivitis, which did not respond to standard treatment. His past medical history was significant for hypertension and tinnitus of the right ear for several months. No other symptoms or signs of systemic diseases were recorded. In the meantime, the patient was admitted to the Department of Cardiology-Intensive Therapy with cardiogenic shock due to complete atrioventricular (AV) block. He underwent temporary pacing, followed by permanent dual-chamber pacemaker insertion. Two weeks later, because of the exacerbation of his eyes problems, he was referred to us with the diagnosis of bilateral anterior uveitis. At presentation, his best-corrected visual acuity (BCVA) in the right eye (RE) was 0.7 and in the left eye (LE) was 0.25. The corneal reflex of the LE was decreased. Ocular examination revealed a non-necrotizing diffuse scleritis, mild paralimbal keratitis, anterior chamber cells (1+) and flare (2+), and posterior synechiae in both eyes, more marked in the LE. The view of the fundus with indirect ophthalmoscope was limited, and the quality of standard photographic documentation was inadequate. Ultrasound evaluation elicited bilateral inflammation of the vitreous body, and exudative retinal detachment. Head computed tomography scans revealed anterior inflammation of the eyewall, retinal detachment, and an enlargement of the left lacrimal gland. Due to progressive visual acuity decline (0.25 in RE; hand motion in LE) within a week, accompanied by the elevation of acute phase reactants, the detailed diagnostic investigation was performed. The erythrocyte sedimentation rate, C-reactive protein, and plasma fibrinogen levels were increased, reaching maximum levels of 88 mm/h, 67 mg/l, and 968 mg/dl, respectively. Serological test for toxocariasis, Lyme disease, tuberculosis, syphilis, viral hepatitis, HIV, rheumatoid factor, anti-CCP, and tumor markers were negative. Despite elevated IgG antibody titers of toxoplasmosis, HSV-1, and CMV, they were not of diagnostic importance. Strongly positive serum cytoplasmic ANCA (c-ANCA), which specifically react with proteinase 3, showed a diffuse granular cytoplasmic staining pattern in a method of indirect immunofluorescence. The urinalysis was unremarkable, and serum creatinine level (0.84 mg/dl), as well as estimated glomerular filtration rate (115.02 ml/min/1.73 m2), were within the normal range. A radiographic study showed a narrowing of right sacroiliac joint space and no chest abnormalities. Abdominal ultrasound examination was normal. Our patient was also HLA-B27 positive. Because c-ANCA were highly specific for GPA, conjunctival and musculocutaneous biopsies were obtained. The histopathological examination did not disclose any evidence of the disease. Notwithstanding the negative biopsy results, we made a tentative diagnosis of GPA based merely on positive c-ANCA and ocular involvement. The patient was referred to the Department of Rheumatology and Internal Medicine, where our diagnosis of GPA was upheld. The patient started therapy with cycles of intravenous steroids and cyclophosphamide along with oral steroids q.d. The response to the treatment was excellent, and ocular inflammation diminished. After the second cycle of therapy, his BCVA increased to 1.0 in RE and 0.2 in LE. The vitritis and exudative retinal detachment resolved completely. Uneventful cataract surgery was performed in the LE that further enhanced his vision to 0.5 after 3 months. At this time, the total dose of cyclophosphamide administered over the 3 years was 9800 mg.