A 39-year-old woman with chronic myeloid leukemia - chronic phase (CML-CP) (BCR-ABL1- positive), treated with imatinib 400 mg for the last 5 years, presented with generalized weakness and loss of appetite for 2 months. She had moderate pallor with splenomegaly (7 cm below the left costal margin). Peripheral blood test revealed hemoglobin count of 8.3 g/dL, platelet of 49×10⁹/L, and total leukocyte of 93.9×10⁹/L. Because transformation to accelerated versus blast crisis phase was clinically suspected, a bone marrow (BM) examination was performed and still showed CML-CP features. Bone marrow trephine biopsy showed hypercellular marrow with multiple large aggregates of Perls-negative pseudo-Gaucher cells, replacing the normal hematopoietic elements (A–D, H&E ×400).

Pseudo-Gaucher or Gaucher-like cells are found in cases with high BM turnover and are formed from the accumulation of leukocyte membrane-derived glucosylceramide inside macrophages. These cells are difficult to differentiate from true Gaucher cells using morphology alone; cytochemistry and electron microscopic findings aid in definitive differentiation. They can also be observed in CML cases; however, multifocal large aggregates of pseudo-Gaucher cells are rarely reported and can create potential confusion with storage cells of Gaucher type. Previous BM examinations of the index case did not show such cells, suggesting they are pseudo-Gaucher cells.