PLASMABLASTIC LYMPHOMA (PBL) AND EXTRAMEDULLARY PLASMABLASTIC TRANSFORMATION OF PLASMA CELL MYELOMA (PCM) : DIAGNOSTIC MORHOLOGICAL, IMMUNOHISTOCHEMICAL AND CLINICAL CHARACTERISTICS
(Abstract release date: 05/19/16)
EHA Library. Vadikolia C. 06/09/16; 134889; PB1989
Dr. Chrissa Vadikolia
Contributions
Contributions
Abstract
Abstract: PB1989
Type: Publication Only
Background
PBL is an aggressive growth of neoplastic cells that resemble B immunoblasts in morphology and are immunophenotypically indistinguishable from plasma cells and lack B cell markers. Even though it was first described in the setting of immune suppression and in fact underlying HIV infection and/or EBER positivity in the neoplastic cells are frequent, it is now increasingly identified in immunocompetent patients with extreme heterogeneity in terms of nodal and extra nodal involvement. However, extramedullary lesions with plasmablastic morphology are not uncommon in patients with PCM, where they usually develop in the course of a refractory disease. The differential diagnosis may be challenging in initial presentation and the complexity is further magnified as both entities have features that overlap with several other lymphomas with plasmablastic morphology.
Aims
To evaluate and compare morphological, immunohistochemical, molecular and clinical characteristics of patients with PBL and plasmablastic transformation of PCM.
Methods
We present patients with documented PBL, with liver and bone involvement, plasmablastic transformation of PCM with multiple sites of involvement in the oral cavity and the gastrointestinal tract and plasmablastic transformation of orbital soft tissue plasmacytomas.
Results
Histopathological examination showed large confluent plasmablasts with abundant cytoplasm and central oval vesicular nuclei with coarse chromatin pattern and prominent nucleoli. They mostly appear as large centroblasts and/or immunoblasts and cannot be readily classified as a B cell or a plasma cell neoplasm or have a more apparent plasma cell differentiation with a paranuclear hof, eccentric large nuclei and basophilic cytoplasm. Background necrosis, karyorrhexis and increased mitotic figures are prominent. Immunohistochemistry is similar with plasma cell neoplasms, positive for CD79a, MUM-1, CD38 and CD138 and the majority negative for CD45 and negative for CD20, PAX-5 and bcl-6. Perhaps the only difference detected in our cohort of patients was the expression of CD56 and CD10 which were negative in PBL. MYC is expressed in about 50% of cases. All patients have very elevated levels of LDH and poor risk cytogenetics. The clinical course is aggressive and response to treatment is poor, with evolution to plasma cell leukaemia in the non PBL patients and overall survival of no more than 6 months from the diagnosis of PBL or the plasmablastic transformation.
Conclusion
When an underlying plasma cell dyscrasia is not yet known, the distinction of a high grade aggressive lymphoma with plasmablastic features may be arbitrary, particularly if there are coexistent marrow involvement, presence of paraproteinaemia, bone lesions and a certain degree of plasmacytic differentiation. It is not clear in the literature whether those are entirely different entities or share a common pathogenetic mechanism. Systemic investigation towards the identification of novel markers and the refinement of our current combination of diagnostic tools may enable a more accurate distinction and definition.
Session topic: E-poster
Keyword(s): Myeloma, Non-Hodgkin's lymphoma, Plasma cells
Type: Publication Only
Background
PBL is an aggressive growth of neoplastic cells that resemble B immunoblasts in morphology and are immunophenotypically indistinguishable from plasma cells and lack B cell markers. Even though it was first described in the setting of immune suppression and in fact underlying HIV infection and/or EBER positivity in the neoplastic cells are frequent, it is now increasingly identified in immunocompetent patients with extreme heterogeneity in terms of nodal and extra nodal involvement. However, extramedullary lesions with plasmablastic morphology are not uncommon in patients with PCM, where they usually develop in the course of a refractory disease. The differential diagnosis may be challenging in initial presentation and the complexity is further magnified as both entities have features that overlap with several other lymphomas with plasmablastic morphology.
Aims
To evaluate and compare morphological, immunohistochemical, molecular and clinical characteristics of patients with PBL and plasmablastic transformation of PCM.
Methods
We present patients with documented PBL, with liver and bone involvement, plasmablastic transformation of PCM with multiple sites of involvement in the oral cavity and the gastrointestinal tract and plasmablastic transformation of orbital soft tissue plasmacytomas.
Results
Histopathological examination showed large confluent plasmablasts with abundant cytoplasm and central oval vesicular nuclei with coarse chromatin pattern and prominent nucleoli. They mostly appear as large centroblasts and/or immunoblasts and cannot be readily classified as a B cell or a plasma cell neoplasm or have a more apparent plasma cell differentiation with a paranuclear hof, eccentric large nuclei and basophilic cytoplasm. Background necrosis, karyorrhexis and increased mitotic figures are prominent. Immunohistochemistry is similar with plasma cell neoplasms, positive for CD79a, MUM-1, CD38 and CD138 and the majority negative for CD45 and negative for CD20, PAX-5 and bcl-6. Perhaps the only difference detected in our cohort of patients was the expression of CD56 and CD10 which were negative in PBL. MYC is expressed in about 50% of cases. All patients have very elevated levels of LDH and poor risk cytogenetics. The clinical course is aggressive and response to treatment is poor, with evolution to plasma cell leukaemia in the non PBL patients and overall survival of no more than 6 months from the diagnosis of PBL or the plasmablastic transformation.
Conclusion
When an underlying plasma cell dyscrasia is not yet known, the distinction of a high grade aggressive lymphoma with plasmablastic features may be arbitrary, particularly if there are coexistent marrow involvement, presence of paraproteinaemia, bone lesions and a certain degree of plasmacytic differentiation. It is not clear in the literature whether those are entirely different entities or share a common pathogenetic mechanism. Systemic investigation towards the identification of novel markers and the refinement of our current combination of diagnostic tools may enable a more accurate distinction and definition.
Session topic: E-poster
Keyword(s): Myeloma, Non-Hodgkin's lymphoma, Plasma cells
Abstract: PB1989
Type: Publication Only
Background
PBL is an aggressive growth of neoplastic cells that resemble B immunoblasts in morphology and are immunophenotypically indistinguishable from plasma cells and lack B cell markers. Even though it was first described in the setting of immune suppression and in fact underlying HIV infection and/or EBER positivity in the neoplastic cells are frequent, it is now increasingly identified in immunocompetent patients with extreme heterogeneity in terms of nodal and extra nodal involvement. However, extramedullary lesions with plasmablastic morphology are not uncommon in patients with PCM, where they usually develop in the course of a refractory disease. The differential diagnosis may be challenging in initial presentation and the complexity is further magnified as both entities have features that overlap with several other lymphomas with plasmablastic morphology.
Aims
To evaluate and compare morphological, immunohistochemical, molecular and clinical characteristics of patients with PBL and plasmablastic transformation of PCM.
Methods
We present patients with documented PBL, with liver and bone involvement, plasmablastic transformation of PCM with multiple sites of involvement in the oral cavity and the gastrointestinal tract and plasmablastic transformation of orbital soft tissue plasmacytomas.
Results
Histopathological examination showed large confluent plasmablasts with abundant cytoplasm and central oval vesicular nuclei with coarse chromatin pattern and prominent nucleoli. They mostly appear as large centroblasts and/or immunoblasts and cannot be readily classified as a B cell or a plasma cell neoplasm or have a more apparent plasma cell differentiation with a paranuclear hof, eccentric large nuclei and basophilic cytoplasm. Background necrosis, karyorrhexis and increased mitotic figures are prominent. Immunohistochemistry is similar with plasma cell neoplasms, positive for CD79a, MUM-1, CD38 and CD138 and the majority negative for CD45 and negative for CD20, PAX-5 and bcl-6. Perhaps the only difference detected in our cohort of patients was the expression of CD56 and CD10 which were negative in PBL. MYC is expressed in about 50% of cases. All patients have very elevated levels of LDH and poor risk cytogenetics. The clinical course is aggressive and response to treatment is poor, with evolution to plasma cell leukaemia in the non PBL patients and overall survival of no more than 6 months from the diagnosis of PBL or the plasmablastic transformation.
Conclusion
When an underlying plasma cell dyscrasia is not yet known, the distinction of a high grade aggressive lymphoma with plasmablastic features may be arbitrary, particularly if there are coexistent marrow involvement, presence of paraproteinaemia, bone lesions and a certain degree of plasmacytic differentiation. It is not clear in the literature whether those are entirely different entities or share a common pathogenetic mechanism. Systemic investigation towards the identification of novel markers and the refinement of our current combination of diagnostic tools may enable a more accurate distinction and definition.
Session topic: E-poster
Keyword(s): Myeloma, Non-Hodgkin's lymphoma, Plasma cells
Type: Publication Only
Background
PBL is an aggressive growth of neoplastic cells that resemble B immunoblasts in morphology and are immunophenotypically indistinguishable from plasma cells and lack B cell markers. Even though it was first described in the setting of immune suppression and in fact underlying HIV infection and/or EBER positivity in the neoplastic cells are frequent, it is now increasingly identified in immunocompetent patients with extreme heterogeneity in terms of nodal and extra nodal involvement. However, extramedullary lesions with plasmablastic morphology are not uncommon in patients with PCM, where they usually develop in the course of a refractory disease. The differential diagnosis may be challenging in initial presentation and the complexity is further magnified as both entities have features that overlap with several other lymphomas with plasmablastic morphology.
Aims
To evaluate and compare morphological, immunohistochemical, molecular and clinical characteristics of patients with PBL and plasmablastic transformation of PCM.
Methods
We present patients with documented PBL, with liver and bone involvement, plasmablastic transformation of PCM with multiple sites of involvement in the oral cavity and the gastrointestinal tract and plasmablastic transformation of orbital soft tissue plasmacytomas.
Results
Histopathological examination showed large confluent plasmablasts with abundant cytoplasm and central oval vesicular nuclei with coarse chromatin pattern and prominent nucleoli. They mostly appear as large centroblasts and/or immunoblasts and cannot be readily classified as a B cell or a plasma cell neoplasm or have a more apparent plasma cell differentiation with a paranuclear hof, eccentric large nuclei and basophilic cytoplasm. Background necrosis, karyorrhexis and increased mitotic figures are prominent. Immunohistochemistry is similar with plasma cell neoplasms, positive for CD79a, MUM-1, CD38 and CD138 and the majority negative for CD45 and negative for CD20, PAX-5 and bcl-6. Perhaps the only difference detected in our cohort of patients was the expression of CD56 and CD10 which were negative in PBL. MYC is expressed in about 50% of cases. All patients have very elevated levels of LDH and poor risk cytogenetics. The clinical course is aggressive and response to treatment is poor, with evolution to plasma cell leukaemia in the non PBL patients and overall survival of no more than 6 months from the diagnosis of PBL or the plasmablastic transformation.
Conclusion
When an underlying plasma cell dyscrasia is not yet known, the distinction of a high grade aggressive lymphoma with plasmablastic features may be arbitrary, particularly if there are coexistent marrow involvement, presence of paraproteinaemia, bone lesions and a certain degree of plasmacytic differentiation. It is not clear in the literature whether those are entirely different entities or share a common pathogenetic mechanism. Systemic investigation towards the identification of novel markers and the refinement of our current combination of diagnostic tools may enable a more accurate distinction and definition.
Session topic: E-poster
Keyword(s): Myeloma, Non-Hodgkin's lymphoma, Plasma cells
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