Cutaneous germinal center cell-derived lymphomas. A clinical histopathological and immunopathological study of 18 cases.

Eighteen cases of cutaneous germinal center cell-derived lymphomas (CGCCL) were classified into 3 types according to Kiel classification: centrocytic lymphomas (CC), 7; centroblastic-centrocytic lymphomas (CB/CC), 9; and centroblastic lymphomas (CB), 2. The duration of the disease was 3-14 months (median 9.5 months) after the first admission. In all cases, monomorphous cutaneous nodules were found as the initial manifestation of the disease. Twelve cases of CGCCL, especially those of CB and CB/CC, initially presented with normochromic anemia, a finding which is helpful in the diagnosis of the disease. Cytomorphologically, CB tumor cells were easily identified, white CC cells were hard to distinguish from the cells of nonepidermotropic cutaneous T cell lymphoma. In many cases, however, electron microscopic examination and cytochemical stains of skin biopsy tissue imprints are useful in diagnosing CGCCL. Immunoenzyme labelling (ABC method) with monoclonal antibodies indicated that B1, K and lambda positivity are very important markers for CGCCL. Our findings also showed a higher percentage of rK type in CGCCL as compared to the Western countries.