Chapter 24 Anaplastic Large-Cell Lymphoma - Dako

Chapter 24 • Anaplastic Large-Cell Lymphoma
General Features
This is a recently recognized entity which expresses CD30 and in many cases (up to
75% in some series) T-cell markers. Many cases have a translocation between chromosome
2 and 5 juxtaposing two genes, nucleophosmin (NPM) and anaplastic lymphoma
kinase (ALK), creating a new fusion protein p80. This may be recognized by nuclear
staining for alk protein.
There appears to be two forms of the disease:
1. The systemic form involves lymph nodes or extranodal sites. It has a bimodal age
distribution, i.e. older children (mostly alk+) and the elderly (many alk-). Alk+ lymphomas
appear to have a better prognosis than other high-grade large-cell lymphomas.
2. The primary cutaneous form (alk-) tends to occur in adults and has a rather indolent
and incurable course although it may spontaneously regress. It may be related to
lympho-matoid papulosis type A.
Histopathology of the Bone Marrow
The neoplastic cells are large, have abundant cytoplasm and large pleo-morphic nuclei
with prominent multiple eosinophilic nucleoli. Large sheets of cells often occur and impart
a cohesive appearance. Marrow involvement may be focal or a diffuse pattern with the
diagnosis resting on the immunohistochemistry.
H&E
CD30
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Guide to Bone Marrow Diagnosis
ALK
EMA
Immunophenotype:
CD30+, EMA+/-, CD43+/-, CD2+/-, CD5+/-, CD4+/-, TIA-1+, GRANZYME B+,
PERFORIN+, CD45-/+, CD25+/-, CD15-/+, CD3+/-, p80+/-
Summary of Key Points
• ALCL has a characteristic morphology and immunophenotype.
• ALCL has two clinical forms: Systemic and primary cutaneous.
• Its cohesive growth pattern may mimic metastatic carcinoma.
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