ALK-Negative ALCL with DUSP22/IRF4 Gene Rearrangement
Lessons From the Friday Unknowns
Sections of the cervical lymph node excision show near total lymph involvement of lymph node by malignant lymphoma comprising large cells with anaplastic morphologic features. The appearance is highly aggressive, with a high number of atypical mitotic figures present.
Submitted immunoperoxidase stained sections show intensely, uniformly positive immunoperoxidase staining of lymphoma cells for CD30. Lymphoma cells additionally show positive immunoperoxidase staining for CD3, CD5, CD2, CD4, CD43, MUM-1, Bcl-2 and CD15. Approximately 40–50% of lymphoma cells show positive immunoperoxidase staining for MYC protein (c-MYC). Variably, very weakly positive immunoreactivity of lymph lymphoma cells for CD8 is suggested. Proliferation of lymphoma cells, as determined by the immunohistologic stain for Ki-67 antigen, is high, with at least 90% of lymphoma cells showing positive nuclear staining for for Ki-67. Lymphoma cells are non-immunoreactive for PAX-5, CD20, CD10, CD7, ALK-1, EMA, TIA-1, Granzyme-B, BCL-6 and BCL-1/cyclin D1.
CD15 expression happens in 15% of ALK negative ALCL
Flow cytometric analysis showed no monotypic B cells and no phenotypically abnormal T cells.
FISH for DUSP22-IRF4 gene rearrangement was positive and negative for TP63 rearrangement.
These findings are supportive of the diagnosis of ALK-negative ALCL with DUSP22/IRF4 gene rearrangement.
Digital slides : bit.ly/3vc3Lsp | Case 3
