MDS with 5q deletion and rare cKIT positive mastocytosis: a diagnostic and therapeutic challenge

BMJ Case Rep. 2019 Apr 20;12(4):e227768. doi: 10.1136/bcr-2018-227768.


A patient with a diagnosis of myelodysplastic syndrome (MDS) with isolated 5q deletion underwent repeat bone marrow biopsy to assess haematological response after 6 months of initial lenalidomide therapy. Subsequent bone marrow biopsies revealed persistent MDS with del(5q) in addition to a small atypical mast cell population with >25% of mast cells with spindle-shaped morphology and immunohistochemistry characteristics consistent with mastocytosis. Molecular testing on the bone marrow was positive for cKIT D816V and the patient was diagnosed with systemic mastocytosis (SM) with an associated haematological neoplasm. MDS with SM is well known to be associated; however, to the best of our knowledge, only one prior case report identifies MDS with del(5q) and associated cKIT D816V positive mastocytosis. While the exact clonal origin of both chromosomal aberrations is unclear, this case illustrates the therapeutic efficacy of lenalidomide in a patient with MDS with del(5q) and rarely associated cKIT positive SM.

Keywords: haematology (incl blood transfusion); malignant and benign haematology; oncology.

Publication types

  • Case Reports

MeSH terms

  • Anemia, Macrocytic / complications*
  • Anemia, Macrocytic / diagnosis
  • Anemia, Macrocytic / genetics
  • Biopsy
  • Bone Marrow / pathology
  • Chromosome Deletion
  • Chromosomes, Human, Pair 5 / genetics
  • Hematologic Neoplasms / complications*
  • Hematologic Neoplasms / drug therapy
  • Hematologic Neoplasms / genetics
  • Hematologic Neoplasms / pathology
  • Humans
  • Immunologic Factors / administration & dosage
  • Lenalidomide / administration & dosage
  • Male
  • Mastocytosis / complications*
  • Mastocytosis / diagnosis
  • Middle Aged
  • Mutation
  • Myelodysplastic Syndromes / complications*
  • Myelodysplastic Syndromes / drug therapy
  • Myelodysplastic Syndromes / genetics
  • Myelodysplastic Syndromes / pathology


  • Immunologic Factors
  • Lenalidomide

Supplementary concepts

  • Chromosome 5q Deletion Syndrome