A case of myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN) successfully treated with lenalidomide.

Lenalidomide is an immunomodulatory drug which is used to treat patients with MDS with deletion 5q chromosomal abnormality. In 2008, WHO introduced a new disease entity called MDS/MPN. No specific treatment for MDS/MPN subtype has yet been identified. We report a patient with MDS/MPN who responded well to lenalidomide therapy.

To the Editor: Lenalidomide is an oral immunomodulatory agent with potent antitumor activity. It was first approved by the US Food and Drug Administration to treat patients with low- and intermediate- Risk MDS with deletion 5q chromosomal abnormality 1. It is also active in other malignancies, such as multiple myeloma and relapsed or refractory mantle cell lymphoma.

In 2008, the WHO introduced a new disease entity called MDS/MPN 2. These are considered to be a rare de novo myeloid neoplasm that exhibit hybrid dysplastic and proliferative features at presentation 3. No specific treatment for MDS/MPN subtype has yet been identified.

We report a patient with MDS/MPN who responded well to lenalidomide therapy. The patient, a 75-year-old white male was referred to our hospital for the evaluation and management of transfusion-dependent anemia and high WBC and platelet count. The patient did not have any major complaints except for being tired and generalized weakness particularly in his legs. His physical examination was unremarkable except for pallor and slightly enlarged spleen. His laboratory values were: WBC 16.6 × 109/L, hemoglobin 8.3 g/dL with a normal MCV, and MCH and a platelet count of 804 × 109/L. His iron studies and folate levels were normal but the B12 level was raised at 1645 pg/mL; His complete metabolic profile and erythropoietin levels were normal. His stool occult blood test X3 was negative and a colonoscopy and esophagogastroduodenoscopy did not reveal any source of bleeding. Ultrasound of the abdomen revealed a slightly enlarged spleen (14.6 cm). He was positive for JAK–2 mutation, but negative for the BCR–ABL transclocation. He was also negative for FGFR1 and PDGFRB rearrangement. A bone marrow aspirate and biopsy revealed a highly cellular marrow (cellularity of 90%) with markedly increased and dysplastic megakaryocytes. Red cell maturation was megaloblastoid. Myeloid maturation was progressive and dysplastic. Ring sideroblasts were readily observed. His cytogenetics revealed a normal karyotype. A diagnosis of MDS/MPN was made. He was started on hydroxyurea which he could not tolerate. He was then started on anagrelide to which he also proved to be intolerant. Although the patient did not have any chromosomal abnormality, particularly deletion 5q chromosomal abnormality, but because of the presence of myelodysplastic features in his bone marrow, he was started on lenalidomide 10 mg orally/daily for 28 days. He received a total of six courses of lenalidimide therapy and following which his WBC and platelet counts returned to normal (WBC 6.5 × 109/L and platelets 374 × 109/L). He remained mildly anemic (Hb 10.5 g/dL), but has become transfusion independent. We believe this is the first case of MDS/MPN showing a remarkable response to lenalidomide therapy. Incidentally, the patient was noted to have a high vitamin B12 level which has been associated with many blood cancers, including myeloproliferative disorders 4.

Conflict of Interest

None declared.