Surgical Pathology Criteria

Primary Systemic Anaplastic Large Cell Lymphoma

Differential Diagnosis

Primary Systemic Anaplastic Large Cell Lymphoma Carcinoma
Usually CD45+ and/or CD45RO+ CD45 and CD45RO negative
ALK positive 60-85% ALK negative
Usually T cell antigen positive T cell antigen negative
ALCL may be EMA and infrequently keratin positive (mostly older reports)

Primary Systemic Anaplastic Large Cell Lymphoma Anaplastic Variant Large B Cell Lymphoma ALK Positive Large B Cell Lymphoma
Marked anaplasia Marked anaplasia Monomorphic with round nuclei
Frequently sinusoidal Frequently sinusoidal Frequently sinusoidal
CD30 >90% CD30 variable CD30 negative
EMA 60% EMA 33% EMA positive
T lineage B lineage B lineage
ALK immunohistology 60-85% positive ALK immunohistology negative ALK immunohistology 100% positive
Majority of ALK positive cases show ALK translocation such as t(2;5) or t(1:2) Lack ALK translocation Rare cases reported with clathrin-ALK t(2:17) gene rearrangement
ALCL may lack T markers and require genetic analysis to determine lineage

Primary Systemic ALCL Classical Hodgkin Lymphoma
PAX5 negative Usually PAX5 positive
Rarely CD15 positive Usually CD15 positive
Usually clusterin positive Rarely clusterin positive
Usually positive for T cell antigens Rarely positive for T cell antigens
Usually T cell receptor gene rearrangement positive Usually T cell receptor gene rearrangement negative
Hallmark cells usually present Reed Sternberg cells usually present
Lacks conspicuously large nucleoli Very large nucleoli

 

Both share anaplastic cytology, T lineage and CD30 reactivity
Primary Systemic ALCL Primary Cutaneous ALCL
Most under age 30 Adult, rare in children
Primary nodal involvement Primary cutaneous involvement
ALK+ 60-85% of cases ALK negative to rare
EMA+ 60% of cases EMA negative to rare
Majority of ALK positive cases show ALK translocation such as t(2;5) or t(1;2) Usually negative for t(2;5) and t(1;2)
  • Secondary nodal involvement may be seen in primary cutaneous cases in the presence of widespread cutaneous disease
  • Secondary cutaneous involvement may be seen in primary systemic cases
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