Primary cutaneous follicle center cell lymphoma with follicular growth pattern

Cutaneous B-cell infiltrates showing a prominent follicular growth pattern with germinal centers are thought by some authors to represent either margi nal zone lymphomas with reactive germinal centers or pseudolymphomas, To es tablish whether a true primary cutaneous follicular lymphoma exists, we stu died biopsies from 15 patients with skin lesions characterized histopatholo gically by the presence of B-cell infiltrates with follicular pattern. Stag ing investigations, including bone marrow biopsy, were negative in patients . All were negative for bcl-2 protein expression and did not present the t( 14;18), In all biopsy specimens neoplastic follicles showed 1 or more morph ologic or immunophenotypic criteria of malignancy (presence of a reduced ma ntle zone, absence of tingible body macrophages, reduced proliferation rate ), In 9 specimens a monoclonal rearrangement of J(H) genes could be detecte d by polymerase chain reaction analysis. After laser beam microdissection, a band of the same length could be observed in 6 probes from different foll icles from the same specimen, indicating the presence of the same monoclona l population of follicle center cells. Follow-up examinations in all patien ts revealed no evidence of extracutaneous spread (mean followup, 48.7 month s), Our study demonstrates that primary cutaneous follicular lymphoma repre sents a distinct entity of the cutaneous B-cell lymphomas, (C) 2000 by The American Society of Hematology.