Primary central nervous system lymphoma masquerading as bilateral vitreous floaters

A 72-year-old female presented with a 6-month history of bilateral floaters and visual blurring. Clinically, the posterior vitreous was cellular bilaterally, with no signs of subretinal infiltrates, retinal vasculitis, disc oedema or macula oedema. A vitreous biopsy and vitrectomy were scheduled following left cataract surgery because of the presence of a dense cataract. One month after cataract surgery, the patient developed signs of florid left arteritis involving the first-order branches of the central retinal artery. A 23-gauge vitreous biopsy and vitrectomy were performed, and preservative-free triamcinolone was injected. Cytology of the biopsy demonstrated benign T-lymphocytes and histiocytes suggestive of mild chronic inflammation only. Magnetic resonance imaging (MRI) of the brain was normal as was lumbar puncture. Subsequently, the patient developed right upper motor neuron facial nerve palsy. MRI imaging on this occasion demonstrated multiple hyper-intense white matter lesions. A third MRI was subsequently obtained due to new neurological deficits and demonstrated enlargement of the pre-existing lesions. Brain biopsy confirmed the presence of primary cerebral lymphoma. The present case highlights the role of various tissue biopsies, including vitreous, cerebrospinal fluid and brain tissue, to establish an elusive diagnosis of primary central nervous system lymphoma presenting as benign vitreous floaters.