Follicular variant of peripheral T-cell lymphoma mimicking follicular lymphoma: a case report with a review of the Literature.

Peripheral T-cell lymphoma (PTCL) with a follicular growth pattern is very rare. Herein, a case of follicular variant of PTCL in a 50-year-old man who complained of tonsillar and generalized lymph node swelling is reported. The resected tonsil revealed a vague nodular growth pattern of atypical cells, medium to large in size, with abundant pale cytoplasm. The lymphoma cells were CD3(+) CD4(+) CD5(+) CD8(-) CD10(+) CD56(-) CD57(-) BCL6(+) PD-1(+) CXCL13(+) and were associated with a meshwork of CD21(+) follicular dendritic cells. Molecular studies revealed clonal rearrangement of the T-cell receptor gamma chain gene but not of the immunoglobulin gene. Cytogenetic analysis disclosed a complex abnormality in 18 of 20 cells with the exclusion of t(5; 9). These findings suggest that the present case is a follicular variant of PTCL derived from follicular T-helper cells.