A case of mast cell leukaemia with exon 9 KIT mutation and good response to imatinib.

Abstract

BACKGROUND:

Mastocytosis is a myeloproliferative neoplasm characterized by the excessive proliferation of mast cells. Mast cell leukaemia (MCL), the aggressive form of this disease, requires cytoreductive therapy, such as cladribine, interferon-alpha-2b and, most recently, tyrosine kinase inhibitors - dasatinib or imatinib.

PATIENT AND METHODS:

We present a case of a 56-yr-old female patient with aleukaemic MCL in whom the typical KIT-D816V mutation was not detected. Sequencing of the entire coding sequence of KIT gene revealed a somatic mutation in exon 9 (p.A502_Y503dup). This mutation was previously reported in patients with gastrointestinal stromal tumours (GIST). Considering the good response to imatinib in such patients, therapy with imatinib was attempted in our patient. The treatment tolerance and outcomes were very good, with reduced mast cell infiltration of the bone marrow, normalization of the serum tryptase concentration and resolution of the clinical signs and symptoms.

CONCLUSIONS:

In the absence of the KIT-D816V in systemic forms of mast cell proliferation, a search for other mutations is indicated, preferably by sequencing the entire KIT gene, as this can influence the choice of treatment. The finding of the p.A502_Y503dup in exon 9, a mutation which has been observed in GIST but not previously reported in any form of aggressive mastocytosis, can be associated with a good response to imatinib in both diseases.

• Authors: Andrzej Mital, Anna Piskorz, Krzysztof Lewandowski, Bartosz Wasąg, Janusz Limon, Andrzej Hellmann
• Journal: European journal of haematology (Eur J Haematol) Vol. 86 Issue 6 Pg. 531-5 (Jun 2011) ISSN: 1600-0609 [Electronic] England
• PMID: 21362052 (Publication Type: Case Reports, Journal Article)
• Copyright: © 2011 John Wiley & Sons A/S.

Chemical References

• Antineoplastic Agents
• Benzamides
• DNA, Neoplasm
• Piperazines
• Pyrimidines
• Imatinib Mesylate
• Proto-Oncogene Proteins c-kit

Topics

• Antineoplastic Agents (therapeutic use)
• Base Sequence
• Benzamides
• DNA Mutational Analysis
• DNA, Neoplasm (genetics)
• Exons
• Female
• Humans
• Imatinib Mesylate
• Leukemia, Mast-Cell (drug therapy, genetics, pathology)
• Middle Aged
• Mutation
• Piperazines (therapeutic use)
• Proto-Oncogene Proteins c-kit (genetics)
• Proto-Oncogenes
• Pyrimidines (therapeutic use)
• Treatment Outcome