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Chronic myelocytic leukemia: ultrastructural histopathology of bone marrow from patients in the chronic phase
Abstract:
We investigated the ultrastructural changes in the hematopoietic microenvironment of the bone marrow obtained from 15 untreated patients with chronic myelocytic leukemia (CML) in the chronic phase by transmission and scanning electron microscopy using the cryofracture technique. Examination of the undecalcified bone marrow specimens confirmed extensive hyperplastic granulopoiesis. In the stroma, fat cells were scarce or absent. Macrophages were increased and scattered throughout the marrow. The cytoplasm contained abundant cellular debris and crystals of the Charcot-Leyden type. Slender reticular cells were inconspicuously located between proliferating myeloid cells. A few foci of fibrosis were occasionally observed. The sinus endothelium generally retained its continuity, and no features suggesting complete deterioration of the sinus were evident. However, certain alterations in the sinus wall were noted in the process of leukemia cell migration. Many cells migrated transcellularly into the circulation through transient large openings in the sinus endothelium.
Insights
This study reveals bone marrow changes in chronic myelocytic leukemia (CML), noting scarce fat cells and increased macrophages with debris. Leukemia cells migrate through transient openings in the sinus endothelium.
Area of Science:
- Hematology
- Oncology
- Cell Biology
Background:
- Chronic myelocytic leukemia (CML) is a myeloproliferative neoplasm.
- Understanding the bone marrow microenvironment in CML is crucial for disease progression insights.
Purpose of the Study:
- To investigate the ultrastructural changes in the bone marrow hematopoietic microenvironment of untreated chronic phase CML patients.
- To elucidate the mechanisms of leukemia cell migration within the bone marrow.
Main Methods:
- Transmission and scanning electron microscopy were employed.
- The cryofracture technique was utilized on undecalcified bone marrow specimens.
- Fifteen untreated CML patients in the chronic phase were included.
Main Results:
- Extensive hyperplastic granulopoiesis was observed.
- Bone marrow stroma showed scarce or absent fat cells and increased macrophages containing cellular debris and Charcot-Leyden crystals.
- Leukemia cell migration occurred transcellularly through transient openings in the sinus endothelium.
Conclusions:
- The bone marrow microenvironment in chronic phase CML exhibits significant alterations, including stromal changes and specific patterns of leukemia cell egress.
- These ultrastructural findings provide insights into CML pathogenesis and cellular trafficking.