PMC6715886_01
A) MRI of large hyperintense mass in proximal femur with osseous involvement and satellite metastatic nodules. B) Whole Body PET/CT showed a large destructive proximal right femur lesion with avid uptake with SUV maximum 13.3.
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Positron emission tomography-computed tomography (PET-CT) confirmed the mass with avid uptake with a maximum standardized uptake values (SUVs) of 13.3 (Fig. 1).
A. Bone marrow aspirate shows adequate cellularity with complete myeloid maturation and essentially normal myeloid to erythroid ratio, consistent with hematologic remission, post treatment for chronic myeloid leukemia (Wright-Giemsa, x1000) and B. the bone marrow core shows normal trilineage hematopoiesis with adequate M:E ratio (H&E, x600. Core biopsy of femur. C) showed immature precursors with oval to irregular nuclei, fine chromatin, eosinophilic cytoplasm and inconspicuous nucleoli associated with fibrosis and scattered eosinophils (H&E, x100). D) immunohistochemical stain highlights the immature precursors/blasts to be CD34 positive (immunoperoxidase, x100).
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The bone biopsy revealed diffuse infiltrate of large, atypical immature cells with eosinophilic cytoplasm, fine chromatin and occasional nucleoli, CD34+ and CD33+ immature myeloid cells, and BCR-ABL1 gene rearrangement by FISH (24.5% nuclei by FISH) (Fig. 2). T315I mutation in a p190 BCR-ABL1 fusion transcript with mutation allele frequency of 31.5% as well as ETV6-BCR fusion. The restaging BM biopsy showed a normocellular marrow with essential normal trilineage hematopoiesis (Fig. 2).