TY - JOUR T1 - Small cell carcinoma presenting as ocular paraneoplastic syndrome due to CRMP-5 JF - Neurosciences Journal JO - Neurosciences (Riyadh) SP - 403 LP - 405 DO - 10.17712/nsj.2020.5.20200095 VL - 25 IS - 5 AU - George Castle AU - Greg Heath Y1 - 2020/10/01 UR - http://nsj.org.sa/content/25/5/403.abstract N2 - We report the case of a lady who presented with 3 weeks of visual floaters and optic disc swelling. Subsequent investigations revealed deep white matter changes on brain imaging, and enlarged mediastinal nodes. The presence of anti-CRMP-5 antibodies finally led to the diagnosis of a paraneoplastic syndrome, and mediastinal lymph node biopsy confirmed the diagnosis of small-cell lung cancer. The learning points from this case include that optic neuritis can be the only presenting feature of a paraneoplastic neurological syndrome, and the usefulness of anti-neuronal antibody measurement as a diagnostic marker of an underlying paraneoplastic disease process. The great challenge is to recognise these tumour-associated autoimmune system presentations early, as they often appear long before the primary cancer is evident. Prompt treatment leads to an earlier reduction in circulating auto-antibody possibly due to reduction in tumour size, and thus less likelihood of permanent neuronal damage. ER -