Patterns of Mycobacterium avium-intracellulare complex infection in duodenal endoscopic biopsies in HIV/AIDS patients.

Mycobacterium avium-intracellulare complex (MAIC) is a nontuberculous opportunistic infection in immunocompromised patients. Involvement of the gastrointestinal tract (GIT) is usually part of a disseminated disease in AIDS patients with a low CD4 count, however with standard antiretroviral therapy (ART), a localized presentation is more likely. It can affect any part of the GIT, mostly the duodenum and typically as patches. Incomplete or refractory ART for HIV-strains, therapy-related side effects, noncompliant or incomplete treatment to previous MAIC infections, superimposed complications and comorbid opportunistic infections may result in atypical clinical, endoscopic and histopathologic manifestations. We performed a retrospective review study retrieving cases of MAIC in duodenal endoscopic biopsy. We found five cases of MAIC in HIV/AIDS patients. They were males with an average age of 40-years. They showed different histopathologic features, variable patterns of MAIC-histiocytic infiltrates, and varying intensity of intracellular acid-fast positive bacilli. Enterocytes vacuolization and transepithelial elimination were also observed. Three cases were associated with cytomegalovirus and cryptococcal infections. A case was complicated by lymphangiectasia-associated protein-losing enteropathy. Initially, three cases were morphologically missed. Ziehl-Neelsen stain helped reach the correct diagnosis. Pathologists have an important role in patients' management by guiding clinicians to the correct diagnosis. Pathologists should be aware of these different histopathologic manifestations, their potential pitfalls, look for certain helpful clues complemented with multiple levels and special stains. In particular, AFB stains are mandatory in all mucosal biopsy specimens from HIV/AIDS patients regardless of their appearances.