Childhood Malignancies / Hodgkin's Non - Hodgkin's Lymphoma / PEDIATRICS

Hodgkin lymphoma must be distinguished from non-cancerous causes of lymph node swelling (such as various infections) and from other types of cancer. Definitive diagnosis is by lymph node biopsy (usually excisional biopsy with microscopic examination). Blood tests are also performed to assess function of major organs and to assess safety for chemotherapy. Positron emission tomography (PET) is used to detect small deposits that do not show on CT scanning. PET scans are also useful in functional imaging (by using a radiolabeled glucose to image tissues of high metabolism). In some cases, a Gallium scan may be used instead of a PET scan.

TypesEdit

There are two main types of Hodgkin lymphoma: classic Hodgkin lymphoma and nodular lymphocyte predominant Hodgkin lymphoma. The prevalence of classic Hodgkin lymphoma and nodular lymphocyte Hodgkin lymphoma are approximately 90% and 10%, respectively.[22][23] The morphology, phenotype, molecular features, and, therefore, the clinical behaviour and presentation of the two types differ.[24]

ClassicEdit

Classic Hodgkin lymphoma (excluding nodular lymphocyte predominant Hodgkin lymphoma) can be subclassified into four pathologic subtypes based upon Reed–Sternberg cell morphology and the composition of the reactive cell infiltrate seen in the lymph node biopsy specimen (the cell composition around the Reed–Sternberg cell(s)).

markers (such as CD20) are not expressed on all cells,[25] Reed–Sternberg cells are usually of B cell origin.[26][27] Although Hodgkin's is now frequently grouped with other B-cell malignancies, some T-cell markers (such as CD2 and CD4) are occasionally expressed.[28] However, this may be an artifact of the ambiguity inherent in the diagnosis.

Hodgkin cells produce interleukin-21 (IL-21), which was once thought to be exclusive to T-cells. This feature may explain the behavior of classic Hodgkin lymphoma, including clusters of other immune cells gathered around HL cells (infiltrate) in cultures.[29]

Nodular lymphocyte predominantEdit

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is another subtype of Hodgkin lymphoma distinct from Classic Hodgkin lymphoma and is characterized by the presence of popcorn cells which express CD20.[23][30] Due to these differences, among others, NLPHL is often treated differently from Classic Hodgkin lymphoma, including using rituximab in combination with AVBD chemotherapy, though individual cases vary and clinical trials are ongoing.[23]

StagingEdit

The staging is the same for both Hodgkin and non-Hodgkin lymphomas.

After Hodgkin lymphoma is diagnosed, a person will be staged: that is, they will undergo a series of tests and procedures that will determine what areas of the body are affected. These procedures may include documentation of their histology, a physical examination, blood tests, chest X-ray radiographs, computed tomography (CT)/Positron emission tomography (PET)/magnetic resonance imaging (MRI) scans of the chest, abdomen and pelvis, and usually a bone marrow biopsy. Positron emission tomography (PET) scan is now used instead of the gallium scan for staging. On the PET scan, sites involved with lymphoma light up very brightly enabling accurate and reproducible imaging.[31] 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.[32]

On the basis of this staging, the person 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) (mostly the cervical region) 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) 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. For localised extranodal extension from mass of nodes that does not advance the stage, subscript "E" is added. Splenic involvement is signified by adding "S" to the stage. The inclusion of "bulky disease" is signified by "X".

• Category

  Lymphoma - Hodgkin - Childhood