Understanding of haematopathology is important in anatomical pathology, as haematologic malignancies are often in the (clinical) differential diagnosis and may mimic small blue round cell tumours or lobular breast carcinoma.
- 1 Bone marrow
- 2 Normal lymph node
- 3 Haematologic neoplasia
- 4 Specific diagnoses
- 5 Cytometry - population cell marker quantification
- 6 Abnormal sign out
- 7 See also
- 8 References
Bone marrows are important for understanding haematopathology. They are dealt with in the bone article.
Normal lymph node
The microscopic lymph node architecture in described the lymph node article, along with B cell maturation and lymph node cell types.
The cells of the lymph node:
- Germinal center:
- Centrocytes - cleaved nucleus.
- Centroblasts - large dark, mitotically active, medullary aspect of germinal center.
- Tingible body macrophages.
- Follicular dendritic cells.
- T lymphocytes.
- Interdigitating dendritic cells.
- Mantle zone:
- Immunoblasts (Memory B cells) - small lymphocytes.
- B lymphocytes.
- Plasma cells.
Historically, haematologic neoplasias were split into leukemia (disease of the bone marrow & blood) and lymphoma (disease in discrete masses -- usually lymph nodes). In the modern day, this distinction has blurred.
At first approximation, these can be thought of as "pre-leukemia/lymphoma".
These predominantly have blood/bone marrow involvement.
These form masses. They typically arise from lymph nodes or aggregates of lymphocytes.
Plasma cell lesions
This subset of haematopathology includes, among others, polycythemia vera. Historically, these were not classified as neoplasias.
- Macrophages eat RBCs, WBCs.
- Thrombocytopenia due to heparin.
- Type 1 - in first two days of exposure - considered non-immune and considered not to be serious.
- Type 2 - in the first 4-10 days - considered serious.
- 50% decline in platelets - within 4-10 days of starting heparin.
- HIT assay - several exist.
Disseminated intravascular coagulation
- Commonly abbreviated DIC.
- Usually associated with sepsis or septic shock.
- Schistocytes (red blood cell fragmentation).
- Pleural petechial haemorrhages.
- Microvascular occlusion.
- Microvascular occlusion is also seen in thrombotic microangiopathies.
Cytometry - population cell marker quantification
- Flow cytometry.
- Laser scanning cytometry (LSC).
- CD3, CD4, CD8, CD5, CD7.
- CD19, CD20, FMC7.
- Kappa, lambda.
- T-cells to B-cells usually 1:1.
- In reactive nodes T-cells predominate.
- Normal thymic tissue has cells that are positive for both CD4 and CD8.
- Kappa (k) and lambda (l) are not expressed by the same cell.
- Rule-of-thumb for normal k:l range is: <6:1 and 1:<3.
- Lambda dominance is less common.
GS guidelines - non-malignant is:
- CD19 ~= CD20.
- CD5 = CD3.
- CD2 > CD3 and CD5.
- CD4 + CD8 ~= CD3.
- CD7 = the smallest number of T-cell.
Abnormal sign out
Lymph Node, Right Posterior Triangle of Neck, Excision: - Lymphoid tissue with abnormal architecture, predominantly small cells. - Case will be sent to hematopathology for opinion.
- URL: http://emedicine.medscape.com/article/1357846-overview. Accessed on: 17 May 2011.
- URL: http://emedicine.medscape.com/article/779097-overview. Accessed on: 23 October 2010.
- Burton, Julian L.; Rutty, Guy N. (2010). The Hospital Autopsy A Manual of Fundamental Autopsy Practice (3rd ed.). Oxford University Press. pp. 209. ISBN 978-0340965146.
- Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 670. ISBN 978-1416031215.
- SB. March 10, 2010.
- GS. LSC Procedure. March 11, 2010.