WBC Neoplasms: OVERVIEW

[liveonearth]

WHITE CELL NEOPLASMS
--malignant proliferation dz is the most imp disorder of WBC
--two main types: lymphoid and myeloid
--lymphoid neoplasms incl: Hodgkin's lymphoma and non-Hodgkin's lymphoma
--myeloid neoplasms incl: proliferation of abn hematopoietic cells (AML, ALL, CML, CLL), myelodysplastic syndromes (MDS), histiocytoses, plasma cell dz (multiple myeloma)
--histological exam (biopsy) of lymph nodes or other involved tissue required for Dx
--in most lymphoid neoplasms, antigen receptor gene rearrangement precedes transformation, can be used to distinguish reactive and malignant lymphoid proliferations
--majority of lymphoid neoplasms are of B-cell origin (80-85%)**
--cause immune abnormalities

ETIO:
--chromosomal translocations and oncogenes present in a majority of WBC neoplasms
--inherited genetic factors
--viruses incl: HTLV-1, EBV, HSGV/HHV-8
--envir: H. pylori (gastric B-cell lymphoma), gluten-sensitive enteropathy (intestinal T-cell lymphoma), HIV (B-cell lymphomas)
--iatrogenic: radiotherapy, chemotherapy (risk of subsequent myeloid & lymphoid neoplasms dt mutagenic effects of cancer tx on hematolymphoid progenitor cells)

LYMPHOCYTIC LEUKEMIA
--widespread involvement of bone marrow (& some peripheral blood)
--S/sx related to suppression of normal hematopoiesis

LYMPHOMA
--proliferation as discrete tissue mass
--Hodgkin (orderly spread) & non-Hodgkin

LYMPHOID NEOPLASMS, FIVE MAIN CATEGORIES BY WHO
1) precursor B-cell (immature)
2) peripheral B-cell (mature)
3) precursor T-cell
4) peripheral T-cell
5) Hodgkin lymphoma (Reed-Sternberg cells & variants)