A CASE OF EXTRACAVITARY PRIMARY EFFUSION LYMPHOMA

Abstract

SESSION TITLE: Medical Student/Resident Disorders of the Mediastinum Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Among HIV related malignancies, primary effusion lymphoma (PEL) is uncommon and represents 1-4% of HIV-associated lymphomas.1 PEL is associated with HHV-8 & EBV, and is monotypic B-cell lymphoma. Despite similar demographic and epidemiologic risk factors, PEL has a distinct genetic and histopathologic profile compared to other HIV-associated non-Hodgkin’s lymphomas (NHL). The classic presentation of PEL is characterized by liquid accumulation of malignant cells associated with serosal surfaces without a localized mass or solid tissue infiltration.1 However, about 1/3 of PEL are extracavitary, and form solid tumors with or without effusions. These mass lesions are often found in the GI tract, spleen, or lymph nodes.2 This can pose a diagnostic challenge, as extracavitary PEL can be mistaken for more common HIV associated lymphomas such as Burkitt’s or DLBCL. CASE PRESENTATION: 41-year-old man presented to clinic with a history of well-controlled HIV on HART therapy, and a complex oncologic history including high grade NHL (likely Burkitt’s lymphoma) diagnosed 17 years prior. His initial course was complicated by CNS involvement, treated with 6 cycles of R-EPOCH, radiation and intra-thecal chemotherapy. He relapsed and underwent autologous stem cell transplant in 2005 with complete remission. Surveillance PET/CT in 2019 demonstrated a 1-cm right-sided lower paratracheal lymph node with mild FDG avidity. The patient endorsed some night sweats but was otherwise asymptomatic. EBUS TBNA confirmed extracavitary primary effusion lymphoma. Immunostains demonstrated lymphoma cells positive for HHV and EBV. Bone marrow biopsy was negative. Notably, this extracavitary PEL was thought to be a second primary malignancy, and not relapse of his prior NHL DISCUSSION: Although relapse of this patient’s prior NHL would be the most expected diagnosis, this case demonstrates two distinct HIV-associated primary lymphomas. Bronchoscopic sampling was critical for pathologic differentiation of these two conditions. The patient’s age, gender, HIV status, and immunohistochemical profile are in line with prior reports,. However, this case is especially unique in that other cases have typically occurred in patients more immunosuppressed than ours. In one of the largest case studies performed, the median CD4 count was 200 and 65% had a history of an AIDS defining condition.2 Other complications of HHV-8 such as Kaposi’s Sarcoma or Multicenter Castleman’s Disease are also common in patients with PEL.2 However prior lymphomas such as Burkitt’s or DLBCL have not been reported as preceding PEL. CONCLUSIONS: This case highlights the spectrum of NHL that can occur in HIV patients, and the importance of appropriate tissue acquisition for clarifying the diagnosis which may be accomplished bronchoscopically. Reference #1: Chen, Y.-B., Rahemtullah, A. and Hochberg, E. (2007), Primary Effusion Lymphoma. The Oncol, 12: 569-576. doi:10.1634/theoncologist.12-5-569 Reference #2: Guillet, S., Gérard, L., Meignin, V., Agbalika, F., Cuccini, W., Denis, B., Katlama, C., Galicier, L. and Oksenhendler, E. (2016), Classic and extracavitary primary effusion lymphoma in 51 HIV-infected patients from a single institution. Am. J. Hematol., 91: 233-237. doi:10.1002/ajh.24251 Reference #3: Chadburn A, Hyjek E, Mathew S, et al. KSHV-positive solid lymphomas represent an extra-cavitary variant of primary effusion lymphoma. Am J Surg Pathol 2004;28:1401–1416. DISCLOSURES: Speaker/Speaker's Bureau relationship with Boehringer-Ingelheim Pharmaceuticals Please note: $5001 - $20000 Added 04/07/2020 by Jaime Betancourt, source=Web Response, value=Honoraria Speaker/Speaker's Bureau relationship with Vapotherm, Inc Please note: $5001 - $20000 Added 04/07/2020 by Jaime Betancourt, source=Web Response, value=Honoraria No relevant relationships by Gwenyth Day, source=Web Response No relevant relationships by Kevin Eng, source=Web Response No relevant relationships by Katy Lawson, source=Web Response