Page 129 - AIDSBK23C

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MALIGNANT LYMPHOMAS

As in other immunodeficiency diseases, the risk for malignant lymphoma is increased
with AIDS. The incidence of non-Hodgkin lymphoma (NHL) with AIDS is 72.8-fold (relative
risk >100), while the risk for Hodgkin lymphoma (HL) is 11.5 fold (relative risk 8). There
appears to be a 5-fold risk for multiple myeloma with AIDS.[560] The organ system
involvement of AIDS-associated malignant lymphomas occurs in two major patterns: (1)
systemic lymphomas comprising a heterogeneous group of cell types and organ involvement and
(2) central nervous system lymphomas. In the former group, more than one organ may be
involved at a time, and extranodal involvement is common (Table 5). The typical variety of
lymphomatous neoplasm seen with AIDS is an intermediate to high grade NHL of B-cell
origin.[392,561]

HODGKIN LYMPHOMA.-- Hodgkin lymphoma (HL) may be seen with increased
frequency in persons infected with HIV, but HL is not part of definitional criteria for diagnosis
of AIDS. There is a 10-fold risk for HL with HIV. Most are males, with a median age of 34
years. HL tends to have a more aggressive course in patients infected with HIV. Injection drug
users constitute the risk group most frequently affected. Hodgkin lymphoma with HIV infection
is more likely to be stage III or IV at presentation (74 to 92%), to have a mixed cellularity
subtype, to have bone marrow involvement, to have noncontiguous spread of tumor, to have
numerous Reed-Sternberg cells, and to show an association with Epstein-Barr virus (EBV)
infection. There is often a prominent fibrohistiocytoid stromal cell proliferation in the involved
lymph nodes. Patients with HIV-associated HL are more likely (70 to 96%) to have "B"
symptoms including fever, night sweats, and/or weight loss >10% of normal body weight. HL
in HIV infected persons is more likely to be accompanied by anemia, leukopenia, or
thrombocytopenia. Extranodal involvement, including bone marrow, liver and spleen, is more
likely to occur.[562]
Cytologic features of classic HL include the presence of a minority of Reed-Sternberg
cells and their variants, which are the true neoplastic cells. The majority of the lesion consists of
an inflammatory background of varying numbers of small lymphocytes, plasma cells,
neutrophils, eosinophils and macrophages. In EBV-associated cases, the macrophages may
exhibit prominent epithelioid features and may form granulomas, but necrosis is rare. The classic
Reed-Sternberg cell is binucleate (mirror images) and the enlarged nuclei have pale, finely
granular chromatin, prominent red macronucleoli and a moderate amount of cytoplasm.
Mononuclear variants of Reed-Sternberg cells have a large, irregular or polylobated nucleus with
a very prominent, single red macronucleolus. The lymphocytic and histiocytic (L&H) variants,
called ‘popcorn cells’, have vesicular, polylobulated nuclei and distinct, small, usually peripheral
nucleoli without perinucleolar halos. Aspirates may be hypo- or hypercellular based upon the
amount of associated sclerosis.[563]
HL in HIV infected persons is more likely to present earlier in the course of infection,
when the CD4 lymphocyte count is higher, than in persons with non-Hodgkin lymphomas.
Generalized lymphadenopathy is likely to be present, and the clinical picture may resemble
persistent generalized lymphadenopathy (PGL). However, mediastinal lymphadenopathy is less
frequent in HIV infected patients with HL. Response to therapy and survival with HL is
lessened when HIV infection is present. Predictors of longer survival with HL in HIV infected