Page 204 - AIDSBK23C

Page 204

IDIOPATHIC THROMBOCYTOPENIC PURPURA.-- There is an increased incidence
of idiopathic thrombocytopenic purpura (ITP) in patients with HIV infection. The appearance of
ITP may precede development of clinical AIDS. Deposition of circulating immune complexes
and complement on platelets and/or circulating anti-platelet antibody are thought to be
mechanisms for HIV-associated ITP. In cases of refractory ITP, splenectomy has shown to be of
benefit but with initially higher relapse rates than in persons without HIV infection.[838]

HISTOLOGIC PATTERNS.-- A variety of histopathologic patterns of red and white pulp
may appear in AIDS. There may be severe lymphocyte depletion with minimal or absent white
pulp, while in other cases macrophages in small groups or clusters (granulomas) may
predominate. In both of these patterns, opportunistic infections or neoplasms are more likely to
be present. However, when plasma cells and immunoblasts are prominent in red and/or white
pulp, infections are not common. Overall, about 40% of AIDS cases have some opportunistic
infection or neoplasm involving the spleen.[837]
In a majority of persons with AIDS, splenic hemosiderin deposition in red pulp is quite
prominent. Iron stains will aid in visualizing these deposits. Examination of sections by
polarized light may reveal crystalline birefringent material associated with injection drug use.
Sometimes large foamy macrophages or multinucleated cells are found without identifiable
infectious agents.

PEDIATRIC FINDINGS.-- At autopsy, young children and infants with HIV infection,
most of who died from AIDS, may show a variety of histologic changes in the spleen. These can
include marked lymphocyte depletion of white pulp and hemophagocytosis. In addition, about
half of cases may demonstrate so-called “kaposiform” lesions composed of foci with spindle
cells admixed with plasma cells, capillaries and hemosiderin-laden macrophages. Such foci bear
a resemblance to Kaposi’s sarcoma with marked inflammation.[831] Splenic smooth muscle
tumors, including leiomyomas and leiomyosarcomas, can appear in association with childhood
AIDS and in association with Epstein-Barr virus infection.[589]