[1333] Extracavitary KSHV+ Large B-Cell Lymphoma: Time To Have a New Name?

Zenggang Pan, Zhengbin Lu, Lanting Liu, David B Wilson, Vishnu Reddy, Huanyou Wang, Yongsheng Ren. Univ. of Alabama at Birmingham; Ameripath, Indianapolis, IN; Univ. of California San Diego

Background: Extracavitary Kaposi sarcoma-associated herpesvirus (KSHV)+ large B-cell lymphoma (EK-LBL) has rarely been observed without effusions. It is uncertain whether it should be considered as a separated entity or a variant of primary effusion lymphoma (PEL). The diagnosis of EK-LBL can be challenging due to lack of a clear definition and a consensus diagnostic term. Here, we reviewed 46 such cases with emphasis on the clinicopathologic features.
Design: 46 EK-LBL cases were collected from the English literature (42) or our files (4). All cases had no effusions before or after presentation. Special studies of our cases included immunostains [CD45, CD20, CD79a, PAX5, CD3, MUM1, EMA, CD30, CD138, immunoglobulin (Ig) light chains, and KSHV], EBV(EBER), and T-cell receptor and Ig gene rearrangements. The results were compared with those summarized from 95 PELs in the literature.

Clinicopathologic features of EK-LBL and PEL

	EK-LBL		Classical PEL
Gender (male/female)	45:1		86:1
HIV	44/46	96%	87/95	92%
KSHV	46/46	100%	61/61	100%
EBER	32/42	76%	26/40	65%
CD45 (LCA)	29/38	76%	65/69	94%
CD20	9/46	20%	4/75	5%
CD79a	8/31	26%	0/13	0%
Ig kappa	4/30	13%	7/33	21%
Ig lambda	10/32	32%	7/33	21%
CD138	22/31	70%	20/33	61%
MUM1	10/10	100%	12/12	100%
CD30	20/34	59%	39/56	70%
EMA	13/22	59%	22/29	76%
IgH rearrangement	15/17	88%	30/42	71%

Results: EK-LBL almost exclusively occurred in HIV+ male, mostly located in the lymph node (28/46), followed by gastrointestinal tract (17). Tumor cells typically exhibited immunoblastic, plasmablastic or anaplastic morphology, with CD45+ but lack of B-cell (CD20, CD79a and PAX5) or T-cell markers. Most cases were EBV+, CD30+, CD138+ and EMA+. It was clinically aggressive; 8 of 16 patients died in 45 days although a few had favorable response.
Classical PEL had similar morphology and immunophenotype to EK-LBL, but it rarely had associated mass lesions and was more often positive for CD45, CD30 and EMA.


Conclusions: Although EK-LBL is generally similar to PEL, it probably should be considered as a distinct entity with a diagnostic term of “extracavitary KSHV+ LBL”.
Category: Hematopathology

Wednesday, March 2, 2011 9:30 AM

Poster Session V # 177, Wednesday Morning