[Diagnostic imaging in immunosuppressed subjects: malignant tumors]

Each state of immunodeficiency is complicated by an increased incidence of certain types of cancer. The risk factors in the development of malignancies increase in a time-dependent relationship with the age of the defect in cell-mediated immunity and some tumors will develop at fairly distinct time intervals during immunodeficiency. Thus, Kaposi's sarcoma appears mostly when the degree of immunodeficiency is slight (average time: 23 months), non-Hodgkin's lymphoma is prevalent in an intermediate phase (average time: 37 months) and some carcinomas will appear only if immunodeficiency lasts many years. Many hypotheses have been suggested as to the biological mechanisms by which an immunity defect contributes to the development of malignancies: the most credible of them is the one suggesting the action of some oncogenic viruses which are not sufficiently controlled by the immune system. Kaposi's sarcomas and non-Hodgkin's lymphomas are the most common types of tumor in AIDS patients. Other tumors--except for Hodgkin's lymphoma--are seldom reported in HIV patients. However, the incidence of carcinomas is thought to be likely to increase in the next few years, because the longer survival of HIV patients, without strengthening their immune system, will unfortunately allow the tumors with longer onset time to develop. As for Kaposi's sarcomas and non-Hodgkin's lymphomas, the major epidemiological data are reported, together with some etiopathogenetic hypotheses and the main clinical and radiologic patterns. Other solid tumors in HIV patients and their clinical and radiologic features are reported too. Our series of cases was collected by the GICAT (Italian Cooperative Group on AIDS-related Tumors) which coordinates epidemiological studies, supports medical research and standardizes the treatment of patients suffering from HIV-related tumors.