The Authors focus on two cases, studied by electron and light microscopy, of Whipple-like disease caused by atypical mycobacteria in AIDS. Differential characteristics between the cases and classical Whipple's disease are analyzed with regard to the diagnostic and therapeutical peculiarities of Mycobacterium avium-intracellulare infection which accounts for over 80% of atypical mycobacterial infections in AIDS. In this regard the Authors stress the role of histological findings of pale blue striated histiocytes as a marker of Mycobacterium avium-intracellulare infection.