Case Report: Unusual inferonasal peripheral retinal involvement in ocular toxoplasmosis: a case report with...

To report the clinical characteristics, diagnostic process, and therapeutic outcome of a case of atypical ocular toxoplasmosis involving the nasal peripheral retina, and to provide reference for the differential diagnosis of this disease.

Clinical data of a 61-year-old female patient with atypical ocular toxoplasmosis in the left eye were retrospectively analyzed, including medical history, ocular examinations, laboratory tests, diagnosis and treatment process, and follow-up results.

The patient presented with "left eye floaters for 3 months". She was initially diagnosed with left eye panuveitis at an external hospital, and received anti-inflammatory treatment including glucocorticoids. Although symptoms partially relieved, the retinal lesion showed progressive enlargement. After admission, comprehensive examinations revealed a 2-3 papillary diameter (PD) round white lesion in the inferonasal peripheral retina of the left eye, accompanied by flocculent vitreous opacity. Aqueous humor inflammatory factors were significantly elevated: interleukin (IL)-8 121.3 pg/mL, IL-6 371.8 pg/mL, and vascular cell adhesion molecule (VCAM) 15637.8 pg/mL, while nucleic acid tests for herpes viruses in aqueous humor were negative. Combined with the history of cat exposure, positive serum and intraocular fluid Toxoplasma gondii test results, and diagnostic Goldmann-Witmer coefficient, the final diagnosis of atypical ocular toxoplasmosis in the left eye was confirmed. After treatment with pyrimethamine combined with glucocorticoids and adjuvant anti-inflammatory therapy, intraocular inflammation was controlled and the lesion became stable.

Ocular toxoplasmosis can present as atypical peripheral retinal lesions, which is easily confused with acute retinal necrosis and other diseases in clinical practice. Definitive diagnosis can be made by combining pet exposure history, laboratory pathogen testing, and characteristic imaging manifestations. Standard anti-parasitic combined with anti-inflammatory therapy can achieve favorable prognosis.