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

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.