The most common symptoms of PIOL include blurred or decreased vision due to tumor cells in the vitreous.
[1] PIOL affects the sub-retinal pigment epithelium (RPE), can invade into the retina, the vitreous, and the optic nerve.
If PIOL is suspected, it is important to first obtain a magnetic resonance image (MRI) of the brain to rule out cerebral involvement (PCNSL).
If MRI is negative, lumbar puncture with cerebrospinal fluid (CSF) cytology should be performed to further rule out CNS disease.
Furthermore, adjunctive testing including polymerase chain reaction (PCR) amplification to identify monoclonal rearrangements of the immunoglobulin heavy chain (IgH) gene (for B-cell lymphomas) or T-cell receptor (TCR, for the very rare T-cell lymphomas) can be performed.