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tend to occur in young males, arise at extranodal sites, and have an aggressive course,
particularly with lack of anaplastic lymphoma kinase (ALK) expression and with low CD4 cell
count. The most common tissue sites of involvement are lung, soft tissue, liver, spleen, skin, and
bone marrow. Positive immunohistochemical markers in cells of ALCL include CD30 in all
cases and the following in 60% or more of cases: CD2, CD3, CD4, CD5, CD43, CD45, and
CD45RO. All cases have TCR gene rearrangement. Though there is often an initial good
response to chemotherapy, the prognosis is poor, with median survival of 5 months.[575]

CUTANEOUS LYMPHOMAS.-- Cutaneous non-Hodgkin lymphomas may be seen in
patients with AIDS. Though mycosis fungoides is the most common primary cutaneous
lymphoma in immunocompetent persons, such lesions are rarely seen in association with AIDS.
Two types of cutaneous lymphoma are seen with AIDS: CD30+ T-cell lymphomas and high
grade B-cell lymphomas. The cutaneous T-cell lymphomas with AIDS are similar to those in
non-HIV-infected persons and frequently present as localized nodules that demonstrate
occasional spontaneous regression. Microscopically, they are anaplastic large cell lymphomas
that mark with Ki-1 (CD30); they may appear in soft tissues and visceral sites as well. The
diffuse large B-cell cutaneous lymphomas with AIDS may remain localized for months without
extra cutaneous spread, but do not regress. AIDS patients present with either T- or B-cell
cutaneous lymphomas at an advanced stage and typically die from opportunistic
infections.[576,577]

PLASMABLASTIC LYMPHOMA.-- A distinctive type of non-Hodgkin lymphoma
called plasmablastic lymphoma is found in persons infected with HIV at sites including oral
cavity, liver/spleen, lymph nodes, gastrointestinal tract, nose or paranasal sinuses, skin, anal
canal, lungs, bone and bone marrow, gonads, CNS, and mediastinum. Half of cases are found in
the oral cavity and the lesions typically involve the mucosa or gingiva and may spread to
underlying structures. Plasmablastic lymphoma is an aggressive, diffuse, B-cell derived lesion
that often leads to death within a year of diagnosis despite aggressive therapy.[578,579]
Immunohistochemical staining shows minimal or absent expression of the leukocyte
common antigen and CD20, the B-cell antigen, while there is diffuse and strong positivity with
the plasma cell markers CD38 and CD138. Epstein-Barr virus can often be identified in the
tumor cells. MYC gene rearrangements can be found in nearly half of cases, and are associated
with worse outcome. Most cases present as stage I or stage IV lesions. Complete response to
chemotherapy is observed in over half of cases.
Cytologically there are large monomorphic cells resembling plasmablasts or
immunoblasts with fairly abundant basophilic cytoplasm, eccentrically situated nuclei with
single or multiple nucleoli, and a paranuclear hof. Lesions are usually cellular with apoptosis,
tingible body macrophages, and increased mitotic figures. Tingible body macrophages impart a
“starry-sky” appearance. The malignant lymphocytes are usually larger and more pleomorphic
than plasma cells of myeloma.[563]

DIFFUSE INFILTRATIVE LYMPHOCYTOSIS SYNDROME.-- Although not a
lymphoma, about 3% of HIV positive patients have visceral organ lymphocytic infiltrates that
may mimic lymphoma. This condition, called diffuse infiltrative lymphocytosis syndrome
(DILS) is seen more frequently in Blacks and in persons with risk factor of homosexuality.
DILS is characterized by a persistent CD8 lymphocytosis and multivisceral CD8 lymphocyte