A Case of Splenic Marginal Zone Lymphoma with Mismatched Morphology and Phenotype, Karyotype and Clinical Course

Background: Splenic marginal zone lymphoma is a rare chronic lymphoproliferative neoplasm with a very indolent clinical course and a noncharacteristic phenotype and karyotype. Peripheral blood morphology can be the first clue to the diagnosis. Methods: Here, we report a case of a patient with splenic marginal zone lymphoma, alive 20 years after initial diagnosis, with very atypical and immature lymphocytes in peripheral blood smear since then. Results: Peripheral blood phenotype and karyotype and pathological analysis of splenectomy sample, as well as the clinical evolution were compatible with splenic marginal zone lymphoma. Conversely, peripheral blood morphology was, from the start, atypical and suggestive of a high-grade lymphoproliferative disorder. Conclusion: Integrating all clinical and laboratory data is essential to make an appropriate diagnosis and guide the therapeutic options offered to patients.