Cutaneous presentation of follicular lymphomas.

The description of primary cutaneous follicular lymphoma has raised interest in the differential diagnosis of this versus disseminated follicular lymphoma involving the skin. We report here on four cases of Stage IV follicular lymphoma, diagnosed in skin biopsy, in which cutaneous lesion was the most noticeable feature of clinical presentation. In all cases, the morphological features were superimposed over typical nodal follicular lymphoma. Apart from classic B-cell markers, they were characterized by CD10 and bcl6 positivity, markers of follicle germinal center cells; and bcl2 expression, with a corresponding t(14;18) translocation in three of three cases examined. In all four cases, bone marrow study and clinical staging revealed disease that had disseminated since diagnosis. Follow-up showed relapsing cutaneous and nodal disease in two cases. The only difference observed with a control group of 10 cases of primary cutaneous follicular lymphoma was the absence in this group of t(14; 18). Disseminated classical follicular lymphoma has to be considered in the differential diagnosis of follicular lymphoma presenting in the skin. This series of cases suggests that the presence of t(14;18) could imply the existence of disease that has disseminated beyond the skin and that cases harboring this translocation could be candidates for systemic polychemotherapy.