OBSOLETE: Primary intraocular lymphoma

Primary intraocular lymphoma (PIOL), also known as primary vitreoretinal lymphoma, is a rare subtype of primary central nervous system lymphoma (PCNSL) that originates within the eye. It is classified as a non-Hodgkin lymphoma, most commonly of the diffuse large B-cell type. This Orphanet entry (279904) is marked as OBSOLETE, as the condition has been reclassified or merged under broader categories such as primary central nervous system lymphoma or ocular adnexal lymphoma in updated nosologies. The ICD-10 code C85.7 corresponds to other specified types of non-Hodgkin lymphoma. Primary intraocular lymphoma primarily affects the vitreous humor, retina, and subretinal pigment epithelium of the eye. It can involve one or both eyes and has a strong tendency to spread to the central nervous system (brain and spinal cord). Key symptoms include blurred vision, floaters, decreased visual acuity, and painless progressive vision loss. Because these symptoms mimic chronic uveitis or vitritis, diagnosis is frequently delayed. Patients may initially be misdiagnosed with inflammatory eye conditions. The disease predominantly affects older adults, typically in the sixth to seventh decades of life, and is more common in immunocompromised individuals, including those with HIV/AIDS or on immunosuppressive therapy. Diagnosis is established through vitreous biopsy with cytological analysis, immunohistochemistry, and molecular studies including interleukin-10 to interleukin-6 ratio measurement in ocular fluids. Treatment typically involves a combination of intravitreal methotrexate or rituximab injections for local ocular disease control, along with systemic high-dose methotrexate-based chemotherapy to address or prevent CNS involvement. Whole-brain and ocular radiation therapy may also be employed. Despite treatment, the prognosis remains guarded, with a significant risk of CNS relapse. Close collaboration between ophthalmologists, neuro-oncologists, and hematologists is essential for optimal management.

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