Classic Hodgkin Lymphoma Flashcards
What is true of all the four subtypes of
CHL?
- derived from B cells
- mononuclear Hodgkin cells and multinucleated RS cells present in all
- reduced expression of B cell antigens
- CD20, CD79a and PAX5
- positive for: CD15 and CD30
- reduced expression of B cell antigens
- variable EBV association (subtype specific)
What are the 4 subtypes of
CHL?
- Nodular Sclerosis
- Lymphocyte rich
- Mixed cellularity
- Lymphocyte depleted
What is the definition of
Nodular sclerosis CHL?
What are key epidemiological facts about
nodular sclerosis CHL?
- accounts for ~70% of cases in resource rich countries
- incidence similar in males and females
- peaks in people 15-35 years of age
What sites does Nodular sclerosis
CHL usually involve?
- medistinum - 80%
- bulky disease- 54%
- splenic or lung - 8-10%
- bone marrow - 3%
- liver- 2%
What are the clinical features
of Nodular sclerosing CHL?
- most are stage II disease
- 40% of patients have B symptoms
- more frequent with advanced stage disease
What is the gross morphology
seen with Nodular sclerosing CHL?
- lymph nodes have a nodular cut surface with fibrous bands being evident
- higher grade lesions (grade 2) may have associated necrosis
- after therapy a persistent mass lesion can be seen
- should be PET negative
What are the microscopic findings
of Nodular Sclerosis CHL?
- dense fibroblast-poor collagen bands
- usually have a thickened lymph node capsule
- Hodgkin RS cells (lacunar cells), mixed cellular infiltrate
- HRS cells more segmented, smaller, less prominent nucleoli than other types of CHL
- with formalin the cytoplasm retracts giving the appearance of sitting in a lacunae
What is a pitfall morphology that can be
seen in Nodular Sclerosing CHL?
- Lacunar cells can form cellular aggregates which may be associated with necrosis and a histocyte reaction
- look like granulomas
- if prominent called Syncitial variant
- Note:
- Grading according to proportion of HRS cells and inflammation may predict prognosis in some settings (more research)
What is the immunophenotype
of HRS cells of Nodular Sclerosing CHL?
- usually not EBV positive (or LMP-1)
- only 10-25% of cases
- CD30- always positive
- CD15- may be negative in 20% of cases
- PAX5 is weakly positive
- CD20- variably expressed and usually weak
- CD79a- only positive in 10%
What are aberrant immunomarkers
that HRS cells can express in
Nodular Sclerosis CHL?
- 5% aberrantly express T cell antigens
- most common: CD2 and CD4
- less common: CD3
- correlated with shorter overall and event-free survival compared to those negative for T cell antigens
IMP: pitfall would be to call this Anaplastic Large Cell lymphoma (ALK -)
- nearly all CHL will be PAX5 positive to help dg
How can Nodular Sclerosis CHL
be graded?
- often done for clinical trials
- Grade 1 and 2
- Grade 2 lesions include:
- >25% nodules show pleomorphic or reticular lymphocyte depletion
- >80% of nodules show features of fibrohistiocytic variant
- >25% of nodules show numerous bizarre anaplastic appearing Hodgkin cells
What is the Fibrihistiocytic variant
of Nodular Sclerosing CHL?
- can mimic a reactive process or mesenchymal neoplasm
- Fibroblasts and histiocytes are abundant
- HRS cells may be difficult to identify
- need PAX5 and CD30
- CD20 will be negative
What is the Syncytial variant of
Nodular Sclerosing CHL?
- lacunar cells form cohesive nests in the centres of the nodules
- necrosis may or may not be present
- if prominent should consider this variant
- may think this is Anaplastic large cell lymphoma
- PAX5 positive
What is the prognosis for
Nodular Sclerosing CHL?
- better than the other types of CHL
- Massive mediastinal disease is an adverse prognostic factor
