Clinicopathologic Features of CD5-positive Nodal Marginal Zone Lymphoma
Clinicopathologic Features of CD5-positive Nodal Marginal Zone Lymphoma
Objectives: To describe the clinicopathologic findings of seven patients with CD5-positive nodal marginal zone lymphoma (NMZL).
Methods: We searched cases of NMZL over a 10-year interval and identified seven cases of CD5-positive NMZL. The clinical, histologic, and immunophenotypic findings of this group were reviewed, and the frequency of dissemination in this group was compared with that of 66 patients with CD5-negative NMZL.
Results: Other than CD5 expression, the histologic and immunophenotypic findings were typical of NMZL. Six (86%) of seven patients had lymphadenopathy above and below the diaphragm, and all six patients assessed had bone marrow involvement. In the CD5-negative group, 28 (42%) patients had lymphadenopathy above and below the diaphragm, and 36 (55%) had bone marrow involvement (P = .045 and P = .037, respectively). Six of seven patients were alive at last follow-up, with a median follow-up of 32 months (3–154 months).
Conclusions: CD5 expression in NMZL correlates with a higher frequency of dissemination, but patients have an indolent clinical course and excellent overall survival.
Nodal marginal zone lymphoma (NMZL) was initially described and designated as monocytoid B-cell lymphoma by Sheibani and colleagues in 1986 based on their observation that the neoplastic cells resembled, in part, monocytoid B cells as seen in pathologic states, such as infection by Toxoplasma gondii. Subsequently, the term nodal marginal zone lymphoma was proposed to emphasize the morphologic and immunophenotypic similarity between NMZL and marginal zone lymphomas involving extranodal sites and the spleen. NMZL is currently defined in the World Health Organization (WHO) classification as a primary nodal B-cell lymphoma that morphologically resembles extranodal or splenic marginal zone lymphoma but without evidence of extranodal or splenic disease. Studies have suggested that NMZL has a distinctive gene expression profile that distinguishes it from other marginal zone lymphomas. NMZL is uncommon, accounting for less than 2% of all lymphomas.
The current WHO classification system does not include immunophenotype in the definition of NMZL. However, NMZL typically has a nonspecific B-cell immunophenotype, positive for monotypic immunoglobulin and pan–B-cell markers and usually negative for CD5, CD10, CD23, BCL-6, and cyclin D1. CD5 is a membrane glycoprotein that is normally present on T-cell subsets as well as memory B cells and appears to have an effect that contributes to B-cell survival. The physiological functions of CD5 in humans, however, remain incompletely understood. Others have reported that CD5 expression can occur in a subset of marginal zone lymphomas and may correlate with dissemination of disease. Ferry et al described three cases of CD5-positive extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) type and proposed that CD5 expression is a marker of dissemination and bone marrow involvement. Subsequent case studies and small series also have suggested that patients with CD5-positive MALT lymphoma more often present with disseminated disease than patients with CD5-negative MALT lymphoma. Similarly, CD5 expression in splenic marginal zone lymphoma has been documented and reported to be associated with an increased propensity for peripheral blood and bone marrow involvement. Other reports have described small subsets of cases of CD5-positive extranodal or splenic marginal zone lymphoma. In contrast, fewer cases of CD5-positive NMZL have been reported in the literature, mostly as case reports or as subsets of larger series. In this study, we have collected the largest case series to date of patients with CD5-positive NMZL to more completely describe the clinicopathologic features of this disease as well as assess the impact of CD5 expression on disease dissemination and prognosis.
Abstract and Introduction
Abstract
Objectives: To describe the clinicopathologic findings of seven patients with CD5-positive nodal marginal zone lymphoma (NMZL).
Methods: We searched cases of NMZL over a 10-year interval and identified seven cases of CD5-positive NMZL. The clinical, histologic, and immunophenotypic findings of this group were reviewed, and the frequency of dissemination in this group was compared with that of 66 patients with CD5-negative NMZL.
Results: Other than CD5 expression, the histologic and immunophenotypic findings were typical of NMZL. Six (86%) of seven patients had lymphadenopathy above and below the diaphragm, and all six patients assessed had bone marrow involvement. In the CD5-negative group, 28 (42%) patients had lymphadenopathy above and below the diaphragm, and 36 (55%) had bone marrow involvement (P = .045 and P = .037, respectively). Six of seven patients were alive at last follow-up, with a median follow-up of 32 months (3–154 months).
Conclusions: CD5 expression in NMZL correlates with a higher frequency of dissemination, but patients have an indolent clinical course and excellent overall survival.
Introduction
Nodal marginal zone lymphoma (NMZL) was initially described and designated as monocytoid B-cell lymphoma by Sheibani and colleagues in 1986 based on their observation that the neoplastic cells resembled, in part, monocytoid B cells as seen in pathologic states, such as infection by Toxoplasma gondii. Subsequently, the term nodal marginal zone lymphoma was proposed to emphasize the morphologic and immunophenotypic similarity between NMZL and marginal zone lymphomas involving extranodal sites and the spleen. NMZL is currently defined in the World Health Organization (WHO) classification as a primary nodal B-cell lymphoma that morphologically resembles extranodal or splenic marginal zone lymphoma but without evidence of extranodal or splenic disease. Studies have suggested that NMZL has a distinctive gene expression profile that distinguishes it from other marginal zone lymphomas. NMZL is uncommon, accounting for less than 2% of all lymphomas.
The current WHO classification system does not include immunophenotype in the definition of NMZL. However, NMZL typically has a nonspecific B-cell immunophenotype, positive for monotypic immunoglobulin and pan–B-cell markers and usually negative for CD5, CD10, CD23, BCL-6, and cyclin D1. CD5 is a membrane glycoprotein that is normally present on T-cell subsets as well as memory B cells and appears to have an effect that contributes to B-cell survival. The physiological functions of CD5 in humans, however, remain incompletely understood. Others have reported that CD5 expression can occur in a subset of marginal zone lymphomas and may correlate with dissemination of disease. Ferry et al described three cases of CD5-positive extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) type and proposed that CD5 expression is a marker of dissemination and bone marrow involvement. Subsequent case studies and small series also have suggested that patients with CD5-positive MALT lymphoma more often present with disseminated disease than patients with CD5-negative MALT lymphoma. Similarly, CD5 expression in splenic marginal zone lymphoma has been documented and reported to be associated with an increased propensity for peripheral blood and bone marrow involvement. Other reports have described small subsets of cases of CD5-positive extranodal or splenic marginal zone lymphoma. In contrast, fewer cases of CD5-positive NMZL have been reported in the literature, mostly as case reports or as subsets of larger series. In this study, we have collected the largest case series to date of patients with CD5-positive NMZL to more completely describe the clinicopathologic features of this disease as well as assess the impact of CD5 expression on disease dissemination and prognosis.
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