The splenic form of mantle cell lymphoma

To describe the clinical, immunophenotypic and molecular features, as well as the clinical course of patients with unusual presentation of mantle cell lymphoma (MCL) purely located to the spleen.

We describe seven patients presented with splenomegaly and a leukemic picture without lymphadenopathy, fulfilling the diagnostic criteria of MCL. In addition to clinical and pathologic features, patients were studied with respect to surface immunophenotype, including adhesion molecule profile, immunohistochemical expression of cyclin-D1 and bcl-1 rearrangement by polymerase chain reaction.

Four patients were male and three female. The median palpable spleen size was 15 cm. A preliminary diagnosis of MCL was made, based on blood cell morphology and immunophenotype. All patients underwent splenectomy for therapeutic purposes. Studies done in blood and splenic lymphocytes revealed the following: 7/7 patients were CD19/CD5, CD20 and CD38 positive; CD10 negative and 6/7 CD23 negative. The adhesion molecule expression pattern was consistent in all patients: L-Selectin and CD11c were negative, CD11alpha and CD18 weakly positive and CD54 strongly positive. The median spleen weight was 1775 g. Histology disclosed a cytologic and architectural pattern consistent with MCL. Cyclin-D1 was positive in 6/6 studied patients. Bcl-1 rearrangement was found in 5/7 patients. Splenectomy was applied as the sole treatment and was beneficial in all patients, with median blood values as following: prior to splenectomy, Ht 29.5%, platelets 110 x 10(9)/l, lymphoma cells 5.0 x 10(9)/L, and at 6 months post-splenectomy, Ht 43%, platelets 311 x 10(9)/l and lymphoma cells 3.0 x 10(9)/L. Of the seven patients, two developed progressive disease 11 and 26 months post-splenectomy. The remaining five are in improving clinical and hematological condition without chemotherapy at a median follow up of 20 months.

We conclude that this presentation represents a separate form of MCL which requires splenectomy. It remains to be seen whether it carries a better prognosis than classical MCL.