SLIDE 3 5/25/19 3
Case 1 - Diagnosis
Anaplastic large cell lymphoma, ALK-negative
Anaplastic large cell lymphoma (ALCL)
- CD30-positive mature T-cell lymphoma with anaplastic morphology
- 2017 WHO Heme classification
– ALCL, ALK-positive (ALCL, ALK+); + for ALK rearrangement – ALCL, ALK-negative (ALCL, ALK-) – Breast implant-associated ALCL (BI-ALCL) - for ALK rearrangement – Primary cutaneous ALCL (C-ALCL)
- Significant clinicopathologic differences between ALCL subtypes;
hence subclassification is important
- Accurate diagnosis - immunohistochemistry and FISH studies
ALCL, ALK-
- Disease predominantly of older adults (40-65 yrs.)
- Nodal or extranodal (soft tissue, bone) presentation
- Advanced stage with B-symptoms
- Histology
– Sheets of cohesive large, anaplastic cells with pleomorphic nuclei – Hallmark cells (indented nuclei with cytoplasmic pseudoinclusions), doughnut cells, multi-nucleated tumor cells frequent – Foci resembling undifferentiated carcinoma or sarcoma seen in a subset of cases – Most cases are more pleomorphic than ALCL, ALK+
ALCL, ALK-
– CD30 - strong and diffuse (> 80% of tumor cells, membranous and Golgi pattern) – variable CD30 staining on a subset of cells NOT ACCEPTABLE - a more accepted diagnosis in this situation is peripheral T-cell lymphoma, not
- therwise specified (PTCL, NOS) with CD30 expression
– ALK1 is NEGATIVE by definition – Loss of one or more pan T-cell markers (CD3, CD2, CD5, CD7) seen in a subset of cases – Usually positive for CD2, CD4, TIA-1, Granzyme B, Perforin – Negative for CD8, CD15, CD56, EBV
– Loss of all pan T-cell antigens and CD45 - not as common as in ALCL, ALK+ but has been reported – CD43 almost always positive (indicates hematopoietic origin) – T-cell receptor gene rearrangement studies can confirm T-cell origin
