Granulomatosis with polyangiitis-associated choroiditis simulating serpiginous choroiditis.

Purpose: To describe a rare presentation of bilateral choroiditis simulating serpiginous choroiditis as an initial ocular manifestation of granulomatosis with polyangiitis (GPA) and highlight clinical features that should prompt consideration of this diagnosis. Observations: A 73-year-old female with renal failure of unknown etiology presented with bilateral vision loss. Fundus examination revealed peripapillary creamy yellow-white choroidal lesions with adjacent atrophy in both eyes. Multimodal imaging demonstrated bilateral choroidal thickening and outer retinal and retinal pigment epithelium atrophy that spared the fovea in the left eye. Review of systems was notable for constitutional, upper and lower respiratory, and otologic symptoms. Extensive infectious and autoimmune testing, including antineutrophil cytoplasmic antibodies, was initially negative. Despite initially negative serologic and biopsy findings, the patient later developed a saddle nose deformity and pulmonary nodules, leading to a diagnosis of seronegative GPA with renal, pulmonary, sinus, and ocular involvement. Treatment with high-dose systemic corticosteroids and local intravitreal corticosteroid implants resulted in quiescence of choroiditis and stabilization of visual acuity over 14 months of follow-up. During a subsequent hospitalization, she demonstrated seroconversion with positive myeloperoxidase (MPO) antibodies, confirming seropositive GPA. Conclusions: Choroiditis is an uncommon posterior segment manifestation of GPA that may mimic infectious or idiopathic inflammatory chorioretinal diseases. This case underscores the importance of considering GPA in patients with choroiditis and systemic features of vasculitis, even in the absence of initial serologic confirmation, as early recognition and treatment are critical to preserving vision.