Cutaneous follicular B-cell lymphoma - Description of a series of 18 cases

The lack of precise and homogeneous criteria for the recognition of primary cutaneous follicular lymphoma has hindered gaining data on the frequency a nd clinical and molecular features of this entity. In the course of a revie w of a series of primary cutaneous lymphoma from different Spanish hospital s, we collected a series of 18 cases of primary cutaneous follicular lympho ma and analyzed its clinical, morphologic, and biologic characteristics. In this review only cases with a follicular pattern of growth, germinal cente r cytology, and restriction to the skin in a minimum follow-up of 6 months have been included. Cases of primary cutaneous follicular lymphoma were cha racterized by the expression of classic markers of the germinal center, suc h as bc16, CD10, and the presence of aggregates of follicular dendritic cel ls. They frequently express bc12 protein, although classical t(14;18) was n ot found in any of the cases analyzed. Analysis of the bc16 noncodifying fi rst exon showed somatic mutations in two of four cases analyzed, as would b e expected in lymphoma deriving from the germinal center. Clinically, most cases showed initial involvement of the head and neck, with relapses in eig ht cases (involving the skin in five cases, both skin and lymph node in two cases, and lymph node in one case). No death attributable to the tumor was recorded. These data seem to imply that follicular lymphoma may present in itially in the skin, lacking the characteristic t(14;18) and having a relat ively indolent course. Recognition of these tumors and elucidation of their molecular alterations could lead to properly adapted staging and treatment protocols for these patients.