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Neutrophilic myelofibrosis presenting as Philadelphia chromosome negative BCR non-rearranged chronic myeloid leukemia
K Stewart1, K C Carstairs, I D Dubé
1Section of Leukemia and Marrow Transplantation, Toronto General Hospital, Ontario, Canada.
Abstract:
Chronic myeloid leukemia consists of Philadelphia chromosome positive disease in 90% of cases, and a further 5%, although Philadelphia chromosome negative, exhibit bcr gene rearrangements consistent with the disease. The remaining 5% of cases have a heterogeneous clinical picture with a course unlike that of classical chronic myeloid leukemia, and may belong to different pathologic entities. We report five cases belonging to the latter group, initially identified as Philadelphia chromosome negative, bcr non-rearranged chronic myeloid leukemia, that developed progressive leucocytosis, absolute monocytosis, myelodysplasia, extramedullary hematopoiesis, and had evidence of myelofibrosis. These cases may represent a distinct clinical entity characterized by neutrophilic myelofibrosis, which can be identified prospectively by clinical and pathologic criteria. Standard therapy for treating chronic myeloid leukemia or idiopathic myelofibrosis may not be appropriate for this group.
Insights
Five Philadelphia chromosome-negative, bcr non-rearranged chronic myeloid leukemia cases developed progressive myelofibrosis. This distinct entity may require different treatments than standard chronic myeloid leukemia or idiopathic myelofibrosis therapies.
Area of Science:
- Hematology
- Oncology
- Pathology
Background:
- Chronic myeloid leukemia (CML) is typically Philadelphia chromosome-positive (Ph+).
- A small subset of Ph-negative cases exhibit bcr gene rearrangements.
- Some Ph-negative, bcr non-rearranged cases present atypically.
Observation:
- Five patients initially diagnosed with Ph-negative, bcr non-rearranged CML were studied.
- These patients exhibited progressive leucocytosis, absolute monocytosis, myelodysplasia, extramedullary hematopoiesis, and myelofibrosis.
- The clinical course differed from classical CML.
Findings:
- The cases represent a distinct clinical entity characterized by neutrophilic myelofibrosis.
- This entity can be identified prospectively using clinical and pathological criteria.
- These findings suggest a unique disease process separate from typical CML.
Implications:
- Standard CML therapies may be ineffective for this distinct group.
- Idiopathic myelofibrosis treatments might also be inappropriate.
- Further research is needed to define optimal therapeutic strategies for this entity.