High-grade B-cell Lymphoma with and Rearrangement Arising from Follicular Lymphoma: Presentation as a Large Peripancreatic Mass.

Follicular lymphoma, the second most common non-Hodgkin lymphoma (NHL), primarily affects adults and shows an indolent clinical course. Rare cases of follicular lymphoma transform to a high-grade B-cell lymphoma with and rearrangements or "double-hit lymphoma". Transformation to a "double-hit lymphoma" portends a worse prognosis and requires aggressive treatment.