Cutaneous follicle center lymphoma: a clinicopathologic study of 19 cases.

Cutaneous follicle center lymphoma (FCL) is reported to have a unique immunophenotype and clinical course as compared with nodal FCL. We studied 19 cases of FCL of the skin using paraffin embedded tissue. An immunohistochemistry panel included CD45, CD3, CD20, CD43, CD21, bcl-2, bcl-6, CD5, and CD10. Molecular studies were performed by polymerase chain reaction for immunoglobulin heavy chain (IgH) and t(14;18). Trisomy 3 was performed by fluorescent in situ hybridization (FISH) in 13 cases. Follow up was obtained in 17 cases (range 3 to 137 months). Patients included 10 females and 9 males ranging in age from 33 to 88 years at first presentation (mean, 64). Twelve of 19 presented in the head and neck and 6 in the trunk and 1 on the arm. All had no known lymph node disease at presentation. Seventeen patients had no nodal disease with a minimum 3 month follow-up; 2/19 had unknown lymph node status with no follow-up. All cases were immunoreactive with CD20 and negative with CD3. Bcl-2 was immunoreactive in 11/18 cases, bcl-6 in 15/15, CD10 in 14/17, CD43 in 2/16 (both were CD10 immunoreactive) and CD5 in 1/15 (it was also bcl-6 immunoreactive). Eight of 18 cases were monoclonal for IgH. Three of 17 showed the presence of t(14;18). FISH was positive in 4 cases for trisomy 3 ranging from 16 to 22% (12% threshold). Follow-up showed no evidence of disease in 14/17 patients (4 to 137 mos). 3/17 patients are alive with disease (17 to 100 mo), and no patients died of disease.