We describe here a case of follicular lymphoma with trisomy 18 without a demonstrable BCL-2 translocation that appeared to transform to a diffuse large cell lymphoma within a single lymph node. The follicular lymphoma, which was associated with strong BCL-2 protein expression in the follicular region, showed absence of BCL-2 protein in the transformed area, despite the continued presence of the chromosomal abnormalities. This case illustrates the ability of tumour cells to alter the expression of the BCL-2 protein within the same lymph node when cells transformed and demonstrates that certain genetic events commonly observed in follicular lymphoma did not play a role in the changing phenotype as the cells transformed.
- follicular lymphoma
- loss of BCL-2 expression