SAGE-Hindawi Access to Research Pathology Research International Volume 2011, Article ID 437431, 3 pages doi:10.4061/2011/437431 Editorial AIDS-Related Pathology Liron Pantanowitz,1 Antonino Carbone,2 and Justin Stebbing3 1 Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA 2 Division of Pathology, Centro di Riferimento Oncologico Aviano, Istituto Nazionale Tumori, Aviano, Italy 3 Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, UK Correspondence should be addressed to Liron Pantanowitz, pantanowitzl@upmc.edu Received 27 April 2011; Accepted 27 April 2011 Copyright © 2011 Liron Pantanowitz et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Since the ﬁrst announcement of acquired immune deﬁciency syndrome (AIDS) in 1981, around 33 million people world- wide are now infected with human immunodeﬁciency virus (HIV) [1]. This pandemic is associated with 6 million new annual HIV infections, resulting in 1.8 million deaths each year due to AIDS. During these past 30 years, an immense amount of knowledge regarding the pathology of HIV/AIDS has accrued. These valiant eﬀorts have provided greater understanding about HIV/AIDS and its associated diseases and have undoubtedly improved the clinical management of aﬄicted persons. Despite this noteworthy eﬀort, however, a tangible cure still seems remote as HIV infected individuals continue to succumb to many AIDS-deﬁning and non-AIDS- deﬁning conditions. In this special issue on AIDS-related pathology, we have assembled diverse papers that showcase this fascinating disease and underscore some of the many unanswered questions. We are fortunate to have some truly superb papers with accompanying striking images. They teach us that the obser- vation of subtle defects can immediately lead to diagnoses with enormous implications for the patient. Such conditions are often seldom observed outside of HIV. Occam’s razor, the principle named after the 14th century philosopher William of Occam, does not apply in this setting. This generalization states that if there are a number of explanations for observed phenomena, the simplest explanation is preferred—called also scientiﬁc parsimony. Rare manifestations of common diseases and common presentations of rare conditions may be seen together; only HIV and its subsequent immunosup- pression link these phenomena. Fortunately, with the advent of HAART in established market economies, the spectrum has changed with a notable shift from infection to cancer and “standard” diseases that non-HIV-infected people are routinely aﬀected by, but often their manifestations have subtle diﬀerences. A variety of diseases may be encountered related directly and/or indirectly to HIV infection. This is well illustrated in the paper reporting the spectrum of pathological man- ifestations of AIDS in a series of 236 autopsied cases in Mumbai, India. This article points out that the vast majority of underlying pathologies discovered by necropsy were either preventable or treatable conditions. The paper dealing with HIV-associated gastrointestinal (GI) disease diagnosed with endoscopic biopsy nicely portrays the variety of inﬂammatory, infectious and neoplastic diseases that may be seen in the upper and lower GI tract. Given the increased frequency of coinfections and broad diversity of diseases likely to be seen, it is not surprising that pathology specimens procured from HIV-infected are diagnostically challenging for anatomic pathologists. This is demonstrated in the beautifully illustrated article about multiple pathologies seen in skin biopsies from patients with HIV/AIDS, as well as the comprehensive review of HIV-related cytopathology. Owing to the progressive reduction of the host immune system, HIV infected individuals are susceptible to many opportunistic infections. As the paper that stems from South Africa on primary oral tuberculosis shows, these often serve as an indicator for HIV infection. The article on Penicillium marneﬀei makes the point that in endemic areas like Hong Kong, disseminated penicilliosis is now included in the list of AIDS-indicator conditions. Human polyomavirus frequently reactivates in individuals infected with HIV, which typically manifests with sinister pathological consequences. This issue is addressed in the paper about novel human