Diffuse large B cell lymphoma classification
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Diffuse large B cell lymphoma may be classified based on location into nodal and extranodal disease and based on molecular, genetic, and immunohistochemical features into more than 20 subgroups.
Classification
Classification Based on Location
Diffuse large B cell lymphoma may be classified based on location:
- Nodal disease
- Extranodal disease
Classification Based on Molecular, Genetic, and Immunohistochemical Features
According to the WHO 2008 classification, diffuse large B cell lymphoma may be classified based on molecular, genetic, and immunohistochemical features into the following:[1]
1. Diffuse large B cell lymphoma, not otherwise specified
A- Morphologic subgroups
- Centroblastic
- Immunoblastic
- Anaplastic
- Other
B- Immunophenotypic subgroups
- Germinal center-derived B-cell (GCB)
- Activated B-cell-like (ABC)
C- Genetic subgroups
- BCL6
- BCL2
- C-MYC
- Other
D- Immunohistochemical subgroups
- CD5-positive de-novo diffuse large B cell lymphoma
- Germinal center B-cell like (GCB)
- Non-germinal center B-cell-like (non-GCB)
2. Diffuse Large B Cell Lymphoma subtypes
- T-cell/histiocyte-rich large B cell lymphoma
- Primary diffuse large B cell lymphoma of the central nervous system (CNS)
- Epstein-Barr virus positive diffuse large B cell lymphoma of the elderly
3. Other lymphomas of large B cells
- Primary mediastinal (thymic) large B-cell lymphoma
- Intravascular large B-cell lymphoma
- DLBCL associated with chronic inflammation
- Lymphomatoid granulomatosis
- ALK-positive LBCL
- Plasmablastic lymphoma
- Large B-cell lymphoma arising in HHV8-associated multicentric Castleman disease
- Primary effusion lymphoma
4. Borderline cases B-cell lymphoma
- Unclassifiable, with features intermediate between DLBCL and Burkitt lymphoma B-cell lymphoma,
- Unclassifiable, with features intermediate between DLBCL and classical Hodgkin lymphoma
Baed on Microscopic pathology
- Three variants are most commonly seen: centroblastic, immunoblastic, and anaplastic.
Centroblastic
- Most cases of are diffuse large B cell lymphoma centroblastic, having the appearance of medium-to-large-sized lymphocytes with scanty cytoplasm.
- Oval or round nuclei containing fine chromatin are prominently visible, having two to four nucleoli within each nucleus.
- Sometimes the tumour may be monomorphic, composed almost entirely of centroblasts.
- However, most cases are polymorphic, with a mixture of centroblastic and immunoblastic cells.
Immunoblastic
- Immunoblasts have significant basophilic cytoplasm and a central nucleolus.
- A tumour can be classified as immunoblastic if greater than 90% of its cells are immunoblasts. This distinction can be problematic, however, because hematopathologists reviewing the microscope slides may often disagree on whether a collection of cells is best characterized as centroblasts or immunoblasts.[2] Such disagreement indicates poor inter-rater reliability.
Anaplastic
- The third morphologic variant, anaplastic, consists of tumour cells which appear very differently from their normal B cell counterparts.
- The cells are generally very large with a round, oval, or polygonal shape and pleomorphic nuclei, and may resemble Hodgkin cells or Reed-Sternberg cells.
References
- ↑ Stein H, Chan JKC, Warnke RA (2008). Diffuse large B-cell lymphoma not otherwise specified. In:Swerdlow SH, Campo E, Harris NL, et al. editors. WHO classification of tumours of haematopoietic and lymphoid tissues. Lyon: IARC. p. 233-7.
- ↑ Harris, N. L.; Jaffe, E. S.; Stein, H; Banks, P. M.; Chan, J. K.; Cleary, M. L.; Delsol, G; De Wolf-Peeters, C; Falini, B; Gatter, K. C. (1994). "A revised European-American classification of lymphoid neoplasms: A proposal from the International Lymphoma Study Group". Blood. 84 (5): 1361–92. PMID 8068936.