Hodgkin's lymphoma classification
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Classification
Classical
Classical Hodgkin's lymphoma (excluding nodular lymphocyte predominant Hodgkin's) can be subclassified into 4 pathologic subtypes based upon Reed-Sternberg cell morphology and the composition of the reactive cell infiltrate seen in the lymph node biopsy specimen. (Template:ICDO)
Classic Hodgkin's Lymphoma (CHL) subtypes:
- Nodular sclerosing CHL is the most common subtype and is composed of large tumor nodules with lacunar RS cells subtype composed of numerous classic often pleomorphic RS cells with only few reactive lymphocytes which may easily be confused with diffuse large cell lymphoma. (C81.3, Template:ICDO)
- Mixed-cellularity subtype is a common subtype and is composed of numerous classic RS cells admixed with numerous inflammatory cells including lymphocytes, histiocytes, eosinophils, and plasma cells. (C81.2, Template:ICDO)
- Lymphocyte-rich and
- lymphocyte depleted are rare subtypes.
Other
Nodular lymphocyte predominant Hodgkin's lymphoma (NLPHL) is no longer classified as a form of classic Hodgkin's lymphoma. This is due to the fact that the RSC variants (popcorn cells) that characterize this form of the disease invariably express B lymphocyte markers such as CD20 (thus making NLPHL an unusual form of B cell lymphoma), and that (unlike classic HL) NLPHL may progress to diffuse large B cell lymphoma. There are small but clear differences in prognosis between the various forms.
Lymphocyte predominant HL is an uncommon subtype composed of vague nodules of numerous reactive lymphocytes admixed with large popcorn-shaped RSC. Unlike classic RSC, the non-classic popcorn-shaped RS cells of NLPHL are CD15 and CD30 negative while positive for the B cell marker CD20. (C81.0, Template:ICDO)
Staging
After Hodgkin's lymphoma is diagnosed, a patient will be staged: that is, they will undergo a series of tests and procedures which will determine what areas of the body are affected. These procedures will include documentation of their histology, a physical examination, blood tests, chest X-ray radiographs, computed tomography (CT) scans or magnetic resonance imaging (MRI) scans of the chest, abdomen and pelvis, and a bone marrow biopsy. Positron emission tomography (PET) scan is now used instead of the gallium scan for staging. In the past, a lymphangiogram or surgical laparotomy (which involves opening the abdominal cavity and visually inspecting for tumors) were performed. Lymphangiograms or laparotomies are very rarely performed, having been supplanted by improvements in imaging with the CT scan and PET scan.
On the basis of this staging, the patient will be classified according to a staging classification (the Ann Arbor staging classification scheme is a common one):
- Stage I is involvement of a single lymph node region (I) or single extralymphatic site (Ie);
- Stage II is involvement of two or more lymph node regions on the same side of the diaphragm (II) or of one lymph node region and a contiguous extralymphatic site (IIe);
- Stage III is involvement of lymph node regions on both sides of the diaphragm, which may include the spleen (IIIs) and/or limited contiguous extralymphatic organ or site (IIIe, IIIes);
- Stage IV is disseminated involvement of one or more extralymphatic organs.
The absence of systemic symptoms is signified by adding 'A' to the stage; the presence of systemic symptoms is signified by adding 'B' to the stage.