| Abstract|| |
Background and Aim: Lennert's lymphoma is a rare variant of peripheral T-cell lymphoma (PTCL) not otherwise specified (NOS) rich in epithelioid histiocytes. This study aims to analyze the clinical, morphologic, and immunophenotypic profile of cases of Lennert's lymphoma from our country and determines the utility of T-cell receptor (TCR) gene rearrangement in the diagnosis. Materials and Methods: All cases diagnosed as Lennert's lymphoma during the period of January 2001 to August 2011 were included in this study. Hematoxylin and eosin (H and E) stained slides and immunohistochemistry results were analyzed and TCR gene rearrangement was performed. Results: There were five cases of Lennert's lymphoma diagnosed in our institution during this period, which included two males and three females. All cases showed effacement of lymph node architecture by diffuse infiltration of small lymphoid T cells [CD3+, CD4+, CD8+, T-cell intracellular antigen 1 (TIA-1+), Granzyme B−] and clusters of epithelioid histiocytes throughout the lymph node and scattered large transformed cells (CD20−, CD30+, CD15−/+). TCR rearrangement was done in three cases by polymerase chain reaction (PCR) and showed the presence of a clonal T-cell population. Conclusions: Lennert's lymphoma constituted 0.11% of all non-Hodgkin lymphomas (NHLs) in our institution. Differentiation from classical Hodgkin's lymphoma is sometimes difficult by morphology and immunohistochemistry alone and TCR gene rearrangement was extremely useful in diagnosis.
Keywords: Hodgkin′s lymphoma, Lennert′s lymphoma, TCR gene rearrangement
|How to cite this article:|
Parimal S, Pai R, Manipadam MT, Nair S. Lennert's lymphoma: Clinicopathological profile of five cases
. Indian J Pathol Microbiol 2013;56:248-51
| Introduction|| |
Lennert's lymphoma was first described by Karl Lennert in 1952,  and later in 1968 by Lennert and Mestdagh.  This entity, initially designated as epithelioid cellular granulomatosis, was characterized by large numbers of epithelioid cells arranged in clusters as well as by the scarcity or absence of typical Hodgkin and Reed-Sternberg cells, which commonly characterize classical Hodgkin's disease. Lennert later assigned it the more neutral name of lymphoepithelioid cell lymphoma in order to distinguish it from cases of Hodgkin's disease with high epithelioid cell content.  In 1975, Lennert himself, with other researchers, stated that the disease should be classified as "lymphoepithelioid cellular lymphoma" and included in the group of non-Hodgkin lymphoma. Later, it became apparent that the so-called Lennert's lymphoma was a T-cell lymphoma, , and in the 1980s and early 1990s, immunohistochemical double-staining techniques revealed that the proliferating cells were CD4-positive, thus indicating that the tumor was of helper T-cell origin. , The neoplastic nature of these CD4-positive T cells was supported by the finding that the T-cell receptor (TCR) beta chain genes in lymphoepithelioid cell lymphomas are clonally rearranged. , However, Lennert's lymphoma was not recognized as a distinct entity in the revised European-American classification of lymphoid neoplasms (REAL classification),  mainly because of issues with reproducibility of diagnosis of this rare lymphoma, especially in the Western countries. Therefore, Lennert's lymphoma was given a provisional cytological category as a lymphoepithelioid cell type, under peripheral T-cell lymphoma, unspecified entity in the REAL classification.
Histopathologic diagnosis is further complicated by the presence of few tumor cells admixed with a large number of epithelioid histiocytes, making it difficult to identify these lymphoma cells in routine hematoxylin - eosin (H and E) sections. In addition, epithelioid histiocytes, observed in Lennert's lymphoma, are also seen in other lymphomas such as Hodgkin's disease and angioimmunoblastic T-cell lymphoma, making the histological criteria for the diagnosis of Lennert's lymphoma rather obscure. In the fourth edition of the World Health Organization (WHO) classification,  Lennert's lymphoma is regarded as a variant of peripheral T-cell lymphoma (PTCL) not otherwise specified (NOS). It consists of small cells with slightly irregular nuclear contours, admixed with a few blasts and some inflammatory elements. Its rarity and the lack of firm diagnostic criteria partly explain why only a few reports on Lennert's lymphoma have been published so far.  This study intends to describe in detail the morphologic and immunohistochemical profile of Lennert's lymphoma and determine the usefulness of TCR gamma gene rearrangement assay in the diagnosis of Lennert's lymphoma and its differentiation from Hodgkin's lymphoma.
| Materials and Methods|| |
Between January 2001 and August 2011, five cases of Lennert's lymphoma were diagnosed in the Department of General Pathology at Christian Medical College and Hospital. Two cases were biopsies sent from other medical centers. Criteria for inclusion in this study were the essential morphologic features in the diagnostic biopsy, as outlined in [Table 1]. Four-micron-thick sections of formalin-fixed, paraffin-embedded lymph node tissue of the selected cases were retrieved and classified after examining the H and E stained sections and immunohistochemistry stained slides.
Immunohistochemistry was performed on the DAKO autostainer in 2008 and 2009 and on the Ventana Benchmark XJ automated immunostainer in 2010 and 2011. The immunohistochemical stains used are enlisted in [Table 2].
DNA was extracted with the Qiagen DNA mini kit (Qiagen, Hilden, Germany).
TCR gamma gene rearrangement assay
DNA was extracted from three of the five samples using the Qiagen DNA mini kit (Qiagen). Three to four 10-μ-thick paraffin-embedded sections of the lymph node were used. The 260/280 ratio was determined using the nanodrop (Nanodrop Technologies, California, USA). Fifty nanograms of DNA was first amplified to determine the quality of DNA using the "amplification control" provided along with the TCR gamma chain gene rearrangement assay (In-Vivo Scribe, California, USA). Further, mix 1 and 2 were amplified as per manufacturer's instructions. The products were detected on a 2% agarose gel before processing them for fragment analysis. Fragment analysis was performed using 1 μl of the polymerase chain reaction (PCR) product that was denatured with formamide and finally detected using the 3130 genetic analyzer (Applied Biosystems, California, USA).
| Results|| |
There were two males and three females. The age of the patients ranged from 27 to 68 years (median 47.5 years, mean 47.8 years). In two cases, biopsies were sent from other hospitals with little clinical details and no follow-up. The remaining all three patients had advanced Ann Arbor stage with elevated serum lactate dehydrogenase level and high - intermediate risk International Prognostic Index (IPI) scores. Two patients (cases 2 and 3) with high - intermediate risk IPI scores were treated with chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisolone or CHOP) and were in complete remission after six courses of chemotherapy. The third patient (case 1), with a high - intermediate risk IPI score, was not willing to take treatment at the institute and so was advised to take cyclophosphamide, etoposide, prednisolone, and procarbazine (CEPP) chemotherapy at the local place with no further follow-up. The clinical features are summarized in [Table 3].
All the cases showed clusters of epithelioid histiocytes [Figure 1]a, surrounded by a diffuse infiltrate of small lymphoid cells [Figure 1]b with round to oval hyperchromatic nuclei, irregular nuclear margins, and scanty cytoplasm. Scattered large cells with immunoblastic morphology were seen. All cases showed few scattered eosinophils, plasma cells, and increased vascularity. Typical binucleate Reed-Sternberg-like cells were not seen in any of the cases. The morphologic findings are summarized in [Table 4].
|Figure 1: (a) Histological appearance of Lennert's lymphoma. Clusters of epithelioid histiocytes seen throughout the lymph node. (b) Highpower magnification showing small lymphoid cells with mild atypia|
Click here to view
In all cases, the small lymphoid cells were CD3+, CD20-, CD4+, and CD8+ [Figure 2]a-d. In three cases, the small lymphoid cells were positive for T-cell intracellular antigen 1 (TIA-1) and negative for Granzyme B. CD21 did not show expanded follicular dendritic cell meshwork in four cases. The large cells were CD30+, CD20-, and CD15-. The immunohistochemistry findings are summarized in [Table 5].
|Figure 2: (a) CD3 positive neoplastic T cells. (b) CD20 immunostaining shows few B lymphocytes among the neoplastic lymphoid cells. (c) CD4 immunostaining; membranous staining in T cells. (d) CD8 immunostaining; membranous staining in T cells|
Click here to view
TCR gamma gene rearrangement assay
Clonal populations of the T cells were detected in three out of five cases by the use of the TCR gamma chain rearrangement assay. Amplification control was satisfactory in all three cases. Two cases had clonal peaks in mix 1. One case showed clonal peaks in mix 1 and 2 using this testing system [Figure 3].
| Discussion|| |
Lennert's lymphoma, a variant of PTCL NOS in the WHO classification of 2008,  is a rare but distinct category, displaying the following characteristics: (1) monomorphic small tumor cells with mild atypia, (2) few scattered immunoblasts, (3) epithelioid cells in dense clusters, (4) absence of both high endothelial venules and follicular dendretic cells (FDC) networks, (5) cytotoxic immunophenotype in the majority of cases with substantial absence of T-cell follicular helper cell marker expression, (6) low proliferation rate, and (7) rare occurrence of clonal B-cell proliferation. 
In the present study, all cases were adults ranging in age from 27 to 68 years with a female predominance (M:F = 2:3).
The lymph node showed diffuse architecture pattern of involvement with essential morphologic features comprising clusters of epithelioid histiocytes as well as varying numbers of atypical small lymphoid cells and scattered large lymphoid cells with immunoblastic morphology.
The small lymphoid cells were CD3+ with mixed populations of CD4 and CD8 in two cases and CD8 predominance in three cases. In three cases, the small lymphoid cells were positive for TIA-1+ and negative for Granzyme B, indicating the non-activated cytotoxic phenotype. There was absence of FDC (CD21-) network in all the four cases and negativity for programmed death 1(PD-1) in three cases analyzed, excluding the diagnosis of angioimmunoblastic T-cell lymphoma. The large cells were positive for CD3 and CD30 and negative for CD15, CD20, and Epstein-Barr virus latent membrane protein 1 (EBV LMP-1) in these cases. The presence of a clonal population of T cells by TCR gene rearrangement assay helped to confirm the T-cell origin of the tumor, making this testing system useful in the diagnosis of Lennert's lymphoma.
The expression of CD4 and CD8 in Lennert's lymphoma has so far been the subject of controversy. Whereas, formerly, the tumor seemed to consist of CD4-positive T cells, ,,, CD8 positivity was later described in cases of Lennert's lymphoma.  Some recent articles have reported CD4-positive as well as CD8-positive cases, , and in our study, two cases showed a mixed population of CD4-positive and CD8-positive cells. The CD8-positive and EBER-positive cases are known to present with a more aggressive behavior.
| Conclusion|| |
Lennert's lymphoma constituted 0.71% of all peripheral T-cell lymphomas in our institution. Distinction from classical Hodgkin's lymphoma is sometimes difficult by morphology and immunohistochemistry alone and TCR gene rearrangement is invaluable in diagnosing these cases. To our knowledge, this is the first case series of Lennert's lymphoma from India.
| References|| |
|1.||Lennert K. Histopathology of non-Hodgkin lymphomas (based on the Kiel classification). Berlin: Springer; 1981. |
|2.||Lennert K, Mestdagh J. Hodgkin's disease with constantly high content of epithelioid cells. Virchows Arch A Pathol Pathol Anat 1968;344:1-20. |
|3.||Lennert K, Mohri N, Stein H, Kaiserling E. The histopathology of malignant lymphoma. Br J Haematol 1975;31:193-203. |
|4.||Nakamura S, Suchi T. A clinicopathologic study of node-based, low-grade, peripheral T-cell lymphoma. Angioimmunoblastic lymphoma, T-zone lymphoma, and lymphoepithelioid lymphoma. Cancer 1991 67:2566-78. |
|5.||Patsouris E, Noel H, Lennert K. Histological and immunohistological findings in lymphoepithelioid cell lymphoma (Lennert's lymphoma). Am J Surg Pathol 1988;12:341-50. |
|6.||Suchi T, Lennert K, Tu LY, Kikuchi M, Sato E, Stansfeld AG, et al. Histopathology and immunohistochemistry of peripheral T cell lymphomas: A proposal for their classification. J Clin Pathol 1987;40:995-1015. |
|7.||Takagi N, Nakamura S, Ueda R, Osada H, Obata Y, Kitoh K, et al. A phenotypic and genotypic study of three node- based, low-grade peripheral T-cell lymphomas: Angioimmunoblastic lymphoma, T-zone lymphoma, and lymphoepithelioid lymphoma. Cancer 1992;69:2571-82. |
|8.||O'Connor NT, Feller AC, Wainscoat JS, Gatter KC, Pallesen G, Stein H, et al. T-cell origin Of Lennert's lymphoma. Br J Haematol 1986;64:521-8. |
|9.||Feller AC, Griesser GH, Mak TW, Lennert K. Lymphoepithelioid lymphoma (Lennert's lymphoma) is a monoclonal proliferation of helper inducer T-cells. Blood 1986;68:663-7. |
|10.||Harris NL, Jaffe ES, Stein H, Banks PM, Chan JK, Cleary ML, et al. A revised European-American classification of lymphoid neoplasms: A proposal from the International Lymphoma Study Group. Blood 1994;84:1361-92. |
|11.||Swerdlow HS, Campo E, Harris NL, Jaffe ES, Pileri S, Stein H, et al. WHO Classification: Pathology and Genetics of Tumors of Haematopoietic and Lymphoid Tissues, 2008, 4 th ed. Pg 308 Lyon: IARC;. |
|12.||Hartmann S, Agostinelli C, Klapper W, Korkolopoulou P, Koch K, Marafioti T, et al. Revising the historical collection of epithelioid cell-rich lymphomas of the Kiel Lymph Node Registry: What is Lennert's lymphoma nowadays? Histopathology 2011;59:1173-82. |
|13.||Feller AC, Griesser GH, Mak TW, Lennert K. Lymphoepithelioid lymphoma (Lennert's lymphoma) is a monoclonal proliferation of helper/inducer T cells. Blood 1986;68:663-67. |
|14.||Montalban C, Obeso G, Gallego A, Castrillo JM, Bellas C, Rivas C. Peripheral T-cell lymphoma: A clinicopathological study of 41 cases and evaluation of the prognostic significance of the updated Kiel classification. Histopathology 1993;22:303-10. |
|15.||Geissinger E, Odenwald T, Lee SS, Bonzheim I, Roth S, Reimer P. Nodal peripheral T-cell lymphomas and, in particular, their lymphoepithelioid (Lennert's) variant are often derived from CD8(+) cytotoxic T-cells. Virchows Arch 2004;445:334-43. |
|16.||Yamashita Y, Nakamura S, Kagami Y, Hasegawa Y, Kojima H, Nagasawa T, et al. Lennert's lymphoma: A variant of cytotoxic T- Cell lymphoma? Am J Surg Pathol 2000;24:1627-33. |
|17.||Kitamura A, Yamashita Y, Sato Y, Hasegawa Y, Kojima H, Nagasawa T, et al. Aggressive Lennert's lymphoma: Report of three cases in comparison to non-aggressive Lennert's Lymphoma. Pathol Int 2005;55:626-31. |
Fellow in Haematopathology, Department of General Pathology, 4th Floor, ASHA Block, Christian Medical College Hospital, Ida Scudder Road, Vellore - 632 004, Tamil Nadu
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]