Mycosis Fungoides : Transformation
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Large Cell Transformation in Mycosis Fungoides (MF): The transformed large cells have a blast-like appearance with vesicular nuclei and prominent nucleoli. Mitotic activity is brisk. There may be considerable nuclear pleomorphism as well as Reed-Sternberg-like cells.
The tumor immunophenotype is that of typical MF. The cells are usually CD4+ and may show loss of CD2, CD5, and CD7. CD8+ variants occur. They may acquire expression of cytotoxic molecules such as perforin, granzyme B, and TIA-1.
Less frequently expressed antigens include CD30 (30-50% of cases), CD25, and CD20. CD30-positive transformation of MF can be distinguished from both cutaneous ALCL and lymphomatoid papulosis on clinical grounds.
The tumor immunophenotype is that of typical MF. The cells are usually CD4+ and may show loss of CD2, CD5, and CD7. CD8+ variants occur. They may acquire expression of cytotoxic molecules such as perforin, granzyme B, and TIA-1.
Less frequently expressed antigens include CD30 (30-50% of cases), CD25, and CD20. CD30-positive transformation of MF can be distinguished from both cutaneous ALCL and lymphomatoid papulosis on clinical grounds.