[Splenic lymphoma with circulating villous lymphocytes. Study of 6 patients]

Splenic lymphoma with circulating villous lymphocytes (SLCVL) is a rare chronic B-type lymphoproliferative disorder, few series having been reported thus far. The major clinical, cytological, immunophenotypic and ultrastructural features, as well as the course and treatment of six cases seen in three hospitals of the Barcelona area in six years are reported herein.

The criteria of Melo et al were followed for the diagnosis of SLCVL. The clinical manifestations at onset and the morphology of lymphocytes from blood and bone-marrow (aspiration and biopsy samples) were analysed. The samples were subjected to cytochemical (acid phosphatase and L-tartaric acid inhibition), immunophenotypic (alkaline immunophosphatase and immunofluorescence) and ultrastructural studies. The histologic study of the spleen of those patients who underwent splenectomy was also performed.

The median age of the series was 63 years (range: 45-86). Five of the patients were women. Anaemia was the commonest clinical finding at onset, and splenomegaly was found in all cases. Villous lymphocytes were found in both peripheral blood, 3% to 85%, and bone-marrow, 31% to 70%; they showed diffuse positivity to acid phosphatase stain, this being inhibited in all cases by L-tartaric acid. None of the patients had associated monoclonal gammopathy. Bone-marrow biopsy was performed in five occasions, showing nodular infiltrative pattern in three cases, interstitial in one and diffuse pattern in another. Nodular infiltration was seen in the white pulp of spleen, with no involvement of the red pulp. The ultrastructural study of villous lymphocytes from peripheral blood or bone-marrow disclosed short, slim villi with narrow bases, no lamellar ribosomal complexes being found. Mature B-type lymphocyte proliferation was present in all instances, showing positivity for surface immunoglobulin; monoclonal antibody CD25 was negative in all cases. Three patients underwent splenectomy, and the remainders received no treatment. The expected survival at three years was 80%.

SLCVL is a rare B-cell chronic lymphoproliferative disorder with recognised morphologic and immunophenotypic characteristics that make it distinguishable from other B-type lymphoproliferative diseases especially hairy cell leukaemia. Its clinical course is chronic and it has good prognosis. Response to splenectomy is usually favourable, although remission of the disease is not achieved.