Light microscopic and electron microscopic diagnosis of gastrointestinal opportunistic infections in HIV-positive patients.

The surgical pathologist is expected to recognise gastrointestinal opportunistic infections in biopsies from HIV-positive patients, and patients immunocompromised iatrogenically by cancer therapy, steroid treatment and transplantation immunosuppression regimes. This review article presents the diagnostic features in gastrointestinal biopsies of microsporidia, cyclospora, isospora, cryptosporidia, mycobacteria, adenovirus, enteropathogenic bacteria, cryptococcus and leishmania. All of these infections have been diagnosed at our hospital in Sydney, Australia, since the AIDS epidemic began. A protocol for the examination and assessment of these gastrointestinal biopsies is presented and discussed.