Page 135 - AIDSBK23C

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OTHER NEOPLASMS

In adults, the only neoplasms that are part of definitional criteria for AIDS are Kaposi
sarcoma, non-Hodgkin lymphomas, and cervical squamous cell carcinomas.[392] Overall, the
incidence for other malignant neoplasms with AIDS is 2.7 times that of the general
population.[544] Persons who are HIV infected have a younger age at diagnosis (47 years) for
malignant neoplasms that are not AIDS-defining, compared with non-HIV infected persons with
the same neoplasms (60 years), and immunosuppression with loss of immune regulation may
play a role in this phenomenon.[584] In the era of antiretroviral therapy (ART) with increasingly
prolonged survival of persons infected with HIV, malignancies now account for over a fourth of
all deaths.[585]
An epidemiologic study of over 50,000 HIV-infected persons followed from 1992 to
2003 indicated the incidence of the following cancers was significantly higher (using
standardized rate ratios, or SRRs) than the general population: anal 42.9, vaginal 21.0, Hodgkin
lymphoma 14.7, liver 7.7, lung 3.3, melanoma 2.6, oropharyngeal 2.6, leukemia 2.5, colorectal
2.3, and renal 1.8. The incidence of prostate cancer was significantly lower among HIV-infected
persons than the general population (SRR, 0.6). Only the relative incidence of anal cancer
increased over time.[586]
Smooth muscle tumors, known as AIDS-associated myoid tumors (AIDS-MTs), may be
seen in children and adults. They are most often seen in children with HIV infection, where they
are a frequent type of neoplasm. The most common locations for childhood smooth muscle
neoplasms include central nervous system, soft tissues, liver, lung, and adrenal. In adults, the
most common locations for EBV associated smooth muscle tumors are brain, liver, spinal cord
and adrenal gland, with multifocality and slow disease progression the typical characteristics.
Other locations in adults include the head and neck region, as well as soft tissues of leg and back.
[587,588] In children, leiomyosarcomas are part of definitional criteria for AIDS.[391] The
relative risk for leiomyosarcoma in children with AIDS is 10,000.[560]
AIDS-MTs are variably aggressive but not often directly a cause of death. Many of these
lesions are associated with Epstein-Barr virus (EBV) infection, as demonstrated by the
appearance of EBV-encoded RNA (EBER) within the neoplastic cells. Histologic types
associated with EBV positivity include leiomyoma, smooth muscle tumour of uncertain
malignant potential (STUMP), leiomyosarcomas, and myopericytoma (MPCT). The EBV-
negative types include leiomyosarcoma, angioleiomyoma, leiomyoma, and STUMP.
Malignancy in AIDS-MTs is characterized by hypercellularity, pleomorphism, increased mitoses
and necrosis. Leiomyosarcomas that are EBV-positive show a fascicular architecture, while
EBV-negative leiomyosarcomas show marked pleomorphism. All AIDS-MTs are desmin,
muscle-specific actin, smooth muscle actin, and h-caldesmon positive by immunohistochemical
staining, though EBV-positive MPCTs and some EBV-positive leiomyosarcomas have
aggregates of desmin-negative round and oval cells.[588,589]
Squamous epithelial lesions including dysplasias and carcinomas can be observed in
persons with HIV infection. The relative risk for cervical cancer is 3 and for anal cancer 30 with
AIDS.[560] One in five HIV-infected women coinfected with HPV, without evidence for
cervical lesions, may develop a squamous intraepithelial lesion within three years, which
emphasizes the importance of Pap smear screening in this population. Cervical dysplasias in
women with HIV infection are more common than in non-HIV-infected women.[590]