Primary mediastinal B-cell lymphoma
Primary mediastinal B-cell lymphoma, abbreviated PMBL, is an uncommon form of large B-cell lymphoma.
It is also known as primary mediastinal large B-cell lymphoma.
- Young adults, more common in females (M:F = 1:2)
It is distinguished from DLBCL based on the patient demographics, radiological staging (showing mainly mediastinal disease) and immunoprofile (typically CD23+/CD30+). PMBCL has a better prognosis than DLBCL.
- Atypical large lymphoid cells - may be morphologically indistinguishable from DLBCL
- Classically associated with:
- Clear cells.
- Other types of DLBCL (radiological assessment is important - PMBCL is centred in the mediastinum)
- B-cell lymphoma with features intermediate between DLBCL and classical Hodgkins lymphoma
- Poorly differentiated carcinoma.
- Pan B-cell markers
- CD10 in minority (~20%)
- CD23 and CD30 expression more common (~70% and ~85% respectively)
- EBV negative
MASS, ANTERIOR MEDIASTINAL, CORE BIOPSY: - LARGE B-CELL LYMPHOMA IN A FIBROTIC BACKGROUND WITH NECROSIS, SEE COMMENT COMMENT: Morphology: Tumour cells: size ~2x a mature lymphocyte, a moderate quantity of grey/basophilic cytoplasm, no clear cells are identified. Cells intermixed with tumour: mature lymphocytes, rare eosinophils. Architecture: no gland formation, discohesive, no follicles apparent, extensive fibrosis. Tumour cells: POSITIVE: CD45, CD20, CD10, BCL-6, BCL-2. NEGATIVE: pankeratin, PLAP, CD3, CD30. Ki-67: 50% of large (lymphoid) cells.
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- van Besien, K.; Kelta, M.; Bahaguna, P. (Mar 2001). "Primary mediastinal B-cell lymphoma: a review of pathology and management.". J Clin Oncol 19 (6): 1855-64. PMID 11251018.