Microscopic description and IHC:

Microscopic examination of cytospin preparations showed large lymphoid cells with variable morphology and moderately round to irregular nuclei as well as prominent nucleoli. Neoplastic cells were diffusely positive for CD7, CD45, CD30, EMA, HHV-8; focally positive for CD138, VS38c and negative for CD3, CD20, CD79 and CD34. EBV with EBER in situ hybridization was negative. Kappa and lambda stained a minority of cells and had a high background staining. The morphologic and immunophenotypic features, were consistent with primary effusion lymphoma.

Discussion:
Flo Cytometry analysis /> </div> <h4>Primary effusion lymphoma (formerly body cavity lymphoma) is one of the least common of acquired immune deficiency syndrome (AIDS) related lymphomas. It accounts for about 4% of all HIV associated non-Hodgkin's lymphomas.(1) The vast majority occur in HIV infected patients, however, this can occur in the absence of infection.(2) The malignant cells of primary effusion lymphoma (PEL) are monoclonal B cells that express cell surface CD38 and contain genomic material from human herpesvirus-8 (100%) and, in many cases, Epstein-Barr virus (80%). It originates on serosal surfaces, including pleura, pericardium and peritoneum.(3) Clinically manifestations depend upon extent and distribution of disease. Symptomatic patients present with dyspnea from pleural/pericardial effusions, abdominal distention, or joint swelling, all related to fluid accumulation. Imaging studies normally reveal evidence of local effusions consistent with accumulation fluid but no detectable mass lesion. However, it may rarely present as an HHV-8 positive solid tumor which predominantly occur in the gastrointestinal tract. Immunohistochemistry is positive for HHV8 (essential for diagnosis), plasma cell associated markers (CD138, VS38c, CD38 , EMA, IRF-4/MUM 1), CD30, CD45; variable for cytoplasmic Ig λ light chain and negative for pan B cel markers (CD19, CD20, CD79 and Pax-5). While present in this case, CD7 positivity is not typical of this disease. In situ EBER (+) is seen in 80% of the cases and flow cytometry is positive for CD45/LCA. </h4> <h4>Primary effusion lymphoma has also been associated with Castleman disease, a lymphoproliferative disorder that causes excessive cytokine release secondary to the expression of the HHV-8 cytokine, vIL-6. This can progress to plasmablastic lymphoma and can also be associated with other plasma cell dyscrasias, Kaposi sarcoma and primary effusion lymphoma (4) as in this case. </h4> </div> </div> <div class=
References:

Chen YB, Rahemtullah A, Hochberg E. Primary effusion lymphoma. Oncologist. 2007 May;12(5):569-76.

Simonelli C, Spina M, Cinelli R, Talamini R, Tedeschi R, Gloghini A, Vaccher E, Carbone A, Tirelli U. Clinical features and outcome of primary effusion lymphoma in HIV-infected patients: a single-institution study. J Clin Oncol. 2003 Nov 1;21(21):3948-54

Foster WR, Bischin A, Dorer R, Aboulafia DM. Human Herpesvirus Type 8-associated Large B-cell Lymphoma: A Nonserous Extracavitary Variant of Primary Effusion Lymphoma in an HIV-infected Man: A Case Report and Review of the Literature. Clin Lymphoma Myeloma Leuk. 2016 Jun;16(6):311-21.

Carbone A, De Paoli P, Gloghini A, Vaccher E. KSHV-associated multicentric Castleman disease: A tangle of different entities requiring multitarget treatment strategies. Int J Cancer. 2015 Jul 15;137(2):251-61

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