Four cases of acute myelofibrosis are contrasted to three cases of acute megakaryocytic leukemia. The cases were clinically indistinguishable. Light microscopic examination of hematoxylin and eosin-stained bone marrow biopsy specimens from the cases of acute myelofibrosis showed a trilinear proliferation of mature and immature hematopoetic cells, increased numbers of mature megakaryocytes, and marked fibrosis. In contrast, the blast cells in the cases of acute megakaryocytic leukemia showed a continuous spectrum of differentiation from small blasts to megakaryoblasts. Immunoperoxidase staining showed the blast cells in all three cases of acute megakaryocytic leukemia to be strongly positive for Factor VIII, a marker of megakaryocytic differentiation. These same blasts did not stain with markers of myelomonocytic (lysozyme), lymphocytic (Hle), and myeloid (leu-MI) differentiation. In contrasts, the blast cells in all four cases of acute myelofibrosis were Factor VIII, Hle, and Leu-MI negative but did occasionally stain with anti-lysozyme.
ASJC Scopus subject areas
- Pathology and Forensic Medicine