How to differentiate between T-cell-rich B-cell lymphoma and lymphocyte-predominant Hodgkin's disease. Evidence for the value of MB1 and 4KB5 immunostaining

T-cell rich B-cell lymphoma: clinical distinctiveness and response to treatment in 45 patients

T-cell rich B-cell lymphoma (TCR-BCL) is a recently described pathologic diagnosis without a place among traditional lymphoma classification systems. In the past, TCR-BCL has been included among other diagnoses, in particular lymphocyte predominant Hodgkin's disease (LPHD). The study of TCR-BCL cohorts may elucidate clinical distinctiveness, response to therapy, and the effect of treatment regimen on outcome. Between 1992 and 1997, a hematopathologist at Memorial Sloan-Kettering Cancer Center (MSKCC) diagnosed 45 patients with TCR-BCL according to published criteria. Clinical data was collected through retrospective chart review and communication with other patient providers. Our patients presented most commonly as males in their fourth decade with advanced stage disease. Three-year overall survival (OS) and failure-free survival (FFS) were 73 and 37%, respectively. Conventional combination chemotherapy regimens were utilized for an aggressive non-Hodgkin's lymphoma (NHL) diagnosis in 26 and for a Hodgkin's disease (HD) diagnosis in 10. Disease-free survival (DFS) was significantly better for NHL (36%) vs. HD (10%) directed chemotherapy at 3 years (p = 0.003). Overall survival at 3 years was not statistically different (62 vs. 79%) due to successful salvage therapy in both groups. It is important to distinguish TCR-BCL from LPHD and classical HD. Advanced stage, extranodal disease, involvement of the mediastinum, mesentery and/or spleen are clinical clues to a TCR-BCL diagnosis. Chemotherapy directed to a NHL diagnosis rather than HD results in a significant improvement in disease-free survival. Initial Hodgkin's disease-directed (HD-directed) chemotherapy should be avoided, although salvage transplantation may result in prolonged survival.

Histiocyte-rich, T-cell-rich B-cell lymphoma: a distinct diffuse large B-cell lymphoma subtype showing characteristic morphologic and immunophenotypic features

AIMS

The clinicopathological features of histiocyte-rich, T-cell-rich B-cell lymphoma (HRTR-BCL) were first recognized in 1992. In this study, 60 cases of HRTR-BCL were analysed in order to provide a detailed morphological and immunophenotypical profile of the disorder.

METHODS AND RESULTS

HRTR-BCL is easily distinguished from other B-cell lymphomas rich in stromal T-cells by (i) a diffuse or vaguely nodular growth pattern, (ii) the presence of a minority population of CD15-, CD20+ large neoplastic B-cells, (iii) a prominent stromal component composed of both T-cells and non-epithelioid histiocytes, and (iv) the scarcity of small reactive B-cells. These criteria also enable a reliable distinction from lymphocyte-rich classical Hodgkin's lymphoma (CHL), from lymphocyte-predominant Hodgkin's lymphoma (LPHL), paragranuloma type and from peripheral T-cell lymphoma. Based on the morphology of the neoplastic cells and on their frequent bcl-6 immunoreactivity, we speculate that HRTR-BCL may be derived from a progenitor cell of germinal centre origin.

CONCLUSIONS

HRTR-BCL presents characteristic clinical features, affecting predominantly middle-aged men who present with advanced stage disease and are at high risk of treatment failure. Considering these distinctive clinicopathological features, recognizing HRTR-BCL as a lymphoma entity may be justified.

Lymphocyte predominance Hodgkin's disease: the use of bcl-6 and CD57 in diagnosis and differential diagnosis

Distinction of lymphocyte predominance Hodgkin's disease (LPHD) from other forms of lymphoma often requires immunohistochemistry (IHC). Most previously published recommended panels include markers to define the large neoplastic cells (for example, CD20, J chain, CD45) as well as the non-neoplastic background cells (CD21, CD45RO, CD57, TiA 1). In the present study we examine the practical use of a double IHC method designed to look simultaneously at two germinal center specific cell types: bcl6+ cells and [bc16+, CD57+] co-positive cells. All 10 nodular LPHD had bcl6+ large cells and numerous CD57+ small background cells, including [bcl6+CD57+] cells in rosettes. One case of LPHD with large cell transformation contained numerous bcl6+ large cells both singly (in areas of typical LPHD) and in sheets (in foci of large cell transformation), many CD57+ small cells but few [bcl6+CD57+] co-positive cells and no rosettes. In none of the five cases of florid progressive transformation of germinal centers were true rosettes seen, although all contained variable numbers of bcl6+ large cells and CD57+ cells. Lymphocyte-rich classic Hodgkin's disease LRCHD cases were notable for bcl6 reactivity in Reed-Sternberg cells in all cases, numerous background small bcl6+ lymphocytes, and rare CD57+ cells. Two phenotypic profiles were associated with the 10 cases of T cell-rich B cell large cell lymphoma (TCRBCL). In the first, group "A," six of six cases had bc16- large cells and few CD57+ small cells, and none had significant numbers of [bcl6+, CD57+] co-positive cells. In the second, group "B," four of four cases had bcl6+ large cells with numerous CD57+ and [bcl6+, CD57+] co-positive cells. These findings not only show that LPHD can be distinguished from its morphologic mimics through identification of specific germinal center cell types, but also identifies a second group of TCRBCL (group "B") whose phenotype suggests it might be an architectural variant of nodular LPHD.

Differential diagnosis between classic Hodgkin's lymphoma, T-cell-rich B-cell lymphoma, and paragranuloma by paraffin immunohistochemistry

There are significant difficulties in the differential diagnosis of lymphomas at the interface between classic Hodgkin's lymphoma and both paragranuloma and T-cell-rich B-cell lymphoma as well as at the interface between T-cell-rich B-cell lymphoma and paragranuloma. We therefore investigated 197 cases (155 classic Hodgkin's lymphomas, 32 T-cell-rich B-cell lymphomas, and 10 paragranulomas) by paraffin immunohistochemistry. Special interest was given to cases with a B-cell phenotype of tumor cells. The reactive inflammatory infiltrate in both classic Hodgkin's lymphoma and T-cell-rich B-cell lymphoma was rich in TIA-1-positive cytolytic lymphocytes, and CD57-positive cells were rarely encountered. In contrast, in paragranuloma CD57-positive cells and small B-lymphocytes predominated the background infiltrate. The tumor cells in cases of classic Hodgkin's lymphoma were positive for CD30 in 95%, for CD15 in 75%, and for CD20 in 22%. Apart from this, vimentin was expressed in >95% of the cases. All cases of T-cell-rich B-cell lymphoma were negative for vimentin, CD30, and CD15. The reactivity of the tumor cells for CD30, CD15, CD20, and vimentin together with the background reactivity for CD57 and TIA-1 seem to reliably discriminate between the entities and should therefore help to increase the interobserver reproducibility of diagnoses in the gray zone around Hodgkin's lymphoma.