Relentless placoid chorioretinitis.

Relentless placoid chorioretinitis (RPC) is a rare, vision-threatening posterior uveitis that predominantly affects young adults. The hallmark clinical findings are numerous scattered placoid chorioretinal lesions involving the midperipheral and far peripheral fundus as well as the posterior pole and a persistent or recurrent course resulting in lesions at different chronological stages, with fresh creamy placoid lesions and healing pigmented lesions being present at the same time. Although RPC is frequently described as a disease that is intermediate between acute posterior multifocal placoid pigment epitheliopathy (APMPPE) and serpiginous choroiditis, it more closely resembles APMPPE. It is important to identify those patients with RPC who present with an APMPPE phenotype so that appropriate immunomodulatory therapy is instituted without delay, as most cases of RPC are refractory to corticosteroid monotherapy. Examination findings may help differentiate RPC and APMPPE. Multimodal imaging, including ultra-widefield imaging, and selective investigations aid in distinguishing RPC from other placoid diseases and types of posterior uveitis.