AIDS-Related Lymphomas Differential Diagnoses

Updated: Sep 09, 2020
  • Author: Christina Poh, MD; Chief Editor: Emmanuel C Besa, MD  more...
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DDx

Diagnostic Considerations

Diagnosis requires histological confirmation of lymphoma in the presence of HIV infection. Like other lymphomas, the Ann Arbor Staging System is utilized in the staging of AIDS-related lymphomas. Of note, staging is not usually valuable for primary CNS and primary effusion lymphomas and thus is not indicated as these malignancies generally remains confined within the CNS/originating body cavity. [27]

Some common AIDS-related lymphoma subtypes are described below.

DLBCL

As the name indicates, the common morphologic features of DLBCL are a relatively large cell size and a diffuse pattern of growth. The cells are about 4 to 5 times larger than a small lymphocyte and usually have a round, vesicular nucleus. The nucleoli are variable in number and position and the cytoplasm is pale or basophilic. The tumor cells typically express CD19, CD20 and have immunophenotypes that resemble DLBCL in the general population.

Diffuse large B cell lymphoma under low magnificat Diffuse large B cell lymphoma under low magnification showing diffuse proliferation of large atypical lymphoid cells in this lymph node specimen.
Diffuse large B cell lymphoma under high power sho Diffuse large B cell lymphoma under high power showing cells that have moderate to abundant cytoplasm, round to irregular nuclear contour, vesicular nuclear chromatin and one to multiple nucleoli. Scattered small mature lymphocytes are seen. Green arrows = atypical lymphocytes; yellow arrows = small lymphocytes.

Burkitt Lymphoma

Burkitt lymphoma has medium-sized tumor cells with a monotonous appearance. The nuclei are round and contain multiple, centrally located nucleoli. The cytoplasm is usually mildly basophilic. The tumor has a high cell turnover, with a proliferation index close to 100 %. Benign macrophages with debris ingested from dead cells may be found within the microscopic field, giving rise to a "starry sky" pattern. Tumor cells are positive for CD20, CD10 and BCL6 but negative for BCL2.

Burkitt lymphoma under low magnification showing s Burkitt lymphoma under low magnification showing sheets of atypical mononuclear cells. Scattered macrophages can be seen (as demonstrated by the green arrows) giving rise to classical "starry-sky" pattern.
Burkitt lymphoma under high magnification showing Burkitt lymphoma under high magnification showing sheets of atypical mononuclear cells. The cells are intermediate to large in size with scant cytoplasm, round to irregular nuclear contour, smudged chromatin and some with nucleoli. Mitosis and apoptosis are frequent with scattered macrophages giving focal "starry-sky" pattern. Green arrows = macrophages; yellow arrows = mitosis.

Plasmablastic lymphoma

Plasmablastic lymphoma forms cohesive masses and has large neoplastic cells. The malignant cells have a "squared off" appearance. The nucleus may be centrally or eccentrically placed. Tumor cells are usually positive for CD38, CD79a, CD138, MUM1, and PRDM1 and negative for CD19,20 and PAX5.

Differential Diagnoses

  • Infections

    o Tuberculosis

    o Toxoplasmosis

    o Disseminated fungal infections

    o Infectious mononucleosis

    o Cat scratch disease

    o Lymphadenopathy associated with HIV

  • Inflammatory conditions

    o Sarcoidosis

  • Malignancies associated with HIV

    o Kaposi sarcoma

    o Cervical cancer

    o Immune reconstitution inflammatory syndrome (IRIS)