Tuberculous uveitis: distribution of Mycobacterium tuberculosis in the retinal pigment epithelium.

The diagnosis of intraocular tuberculosis has been a challenge until the introduction of polymerase chain reaction (PCR) to detect the mycobacterial-specific DNA sequence in the intraocular fluids. Such investigations have confirmed diverse manifestations of intraocular tuberculosis including retinal vasculitis and serpiginouslike choroiditis. The latter may manifest with multifocal lesions involving the inner choroid, which coalesce to form a geographic pattern simulating serpiginous choroiditis. Although, clinically, the choroiditis appears to involve primarily the inner choroid and retinal pigment epithelium (RPE), the presence of mycobacterium at these anatomic sites has not been documented. Herein, we describe a case of panuveitis that was clinically of unknown cause but for which histopathologic examination of the globe disclosed selective distribution of acid-fast organisms in the RPE. These were confirmed to be Mycobacterium tuberculosis by microdissection of the RPE, followed by real-time PCR.