A 22-year-old woman presented with fatigue and leukocytosis without organomegaly and a referral diagnosis of chronic myeloproliferative neoplasm without BCR::ABL1 translocation or JAK2 mutation. Complete blood count showed leukocytosis (white blood cell [WBC], 21.8 × 109/L), anemia (hemoglobin, 11.1 gm/dL), and thrombocytopenia (platelets, 114 × 109/L) with neutrophilia (15.9 × 109/L), eosinophilia (1.74 × 109/L), and rare circulating blasts. Bone marrow (BM) biopsy was hypercellular (∼100%) with myeloid hyperplasia, atypical megakaryocytic hyperplasia, and clusters of foamy histiocytes (panel A, ×400, hematoxylin-eosin stain) highlighted with periodic acid–Schiff stain with fast green counterstain (panel B, ×400). BM smears showed left-shifted myeloid hyperplasia with numerous pseudo-Gaucher cells/sea blue histiocytes with abundant blue and variably lamellar cytoplasm (panel C; ×1000, Wright-Giemsa). Karyotyping detected a t(5;12) (panel D), and fluorescence in situ hybridization confirmed the presence of PDGFRB (panel E) and ETV6 rearrangement in 78% of analyzed cells. The patient was treated with imatinib (400 mg daily) and achieved remission with a WBC of 8.9 × 109/L at 1-month follow-up.
Sea-blue histiocytes and pseudo-Gaucher cells are a hallmark of increased cell turnover and characteristically associated with chronic myeloid leukemia BCR::ABL1+. To our knowledge, this is the first report describing increased pseudo-Gaucher cells in association with a myeloid neoplasm with eosinophilia and PDGFRB rearrangement, expanding the spectrum of this morphologic finding.
A 22-year-old woman presented with fatigue and leukocytosis without organomegaly and a referral diagnosis of chronic myeloproliferative neoplasm without BCR::ABL1 translocation or JAK2 mutation. Complete blood count showed leukocytosis (white blood cell [WBC], 21.8 × 109/L), anemia (hemoglobin, 11.1 gm/dL), and thrombocytopenia (platelets, 114 × 109/L) with neutrophilia (15.9 × 109/L), eosinophilia (1.74 × 109/L), and rare circulating blasts. Bone marrow (BM) biopsy was hypercellular (∼100%) with myeloid hyperplasia, atypical megakaryocytic hyperplasia, and clusters of foamy histiocytes (panel A, ×400, hematoxylin-eosin stain) highlighted with periodic acid–Schiff stain with fast green counterstain (panel B, ×400). BM smears showed left-shifted myeloid hyperplasia with numerous pseudo-Gaucher cells/sea blue histiocytes with abundant blue and variably lamellar cytoplasm (panel C; ×1000, Wright-Giemsa). Karyotyping detected a t(5;12) (panel D), and fluorescence in situ hybridization confirmed the presence of PDGFRB (panel E) and ETV6 rearrangement in 78% of analyzed cells. The patient was treated with imatinib (400 mg daily) and achieved remission with a WBC of 8.9 × 109/L at 1-month follow-up.
Sea-blue histiocytes and pseudo-Gaucher cells are a hallmark of increased cell turnover and characteristically associated with chronic myeloid leukemia BCR::ABL1+. To our knowledge, this is the first report describing increased pseudo-Gaucher cells in association with a myeloid neoplasm with eosinophilia and PDGFRB rearrangement, expanding the spectrum of this morphologic finding.
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![A 22-year-old woman presented with fatigue and leukocytosis without organomegaly and a referral diagnosis of chronic myeloproliferative neoplasm without BCR::ABL1 translocation or JAK2 mutation. Complete blood count showed leukocytosis (white blood cell [WBC], 21.8 × 109/L), anemia (hemoglobin, 11.1 gm/dL), and thrombocytopenia (platelets, 114 × 109/L) with neutrophilia (15.9 × 109/L), eosinophilia (1.74 × 109/L), and rare circulating blasts. Bone marrow (BM) biopsy was hypercellular (∼100%) with myeloid hyperplasia, atypical megakaryocytic hyperplasia, and clusters of foamy histiocytes (panel A, ×400, hematoxylin-eosin stain) highlighted with periodic acid–Schiff stain with fast green counterstain (panel B, ×400). BM smears showed left-shifted myeloid hyperplasia with numerous pseudo-Gaucher cells/sea blue histiocytes with abundant blue and variably lamellar cytoplasm (panel C; ×1000, Wright-Giemsa). Karyotyping detected a t(5;12) (panel D), and fluorescence in situ hybridization confirmed the presence of PDGFRB (panel E) and ETV6 rearrangement in 78% of analyzed cells. The patient was treated with imatinib (400 mg daily) and achieved remission with a WBC of 8.9 × 109/L at 1-month follow-up.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/140/6/10.1182_blood.2022016602/3/m_bloodbld2022016602f1.png?Expires=1765011373&Signature=JFXebxjKkRKYNIOcLycYkcR6od6Hgnwug~VhEMg3xHdbMIk3PtHZbdjYc7LzLZoqSRGqU76lGlC3AvI0zT5mZg7fxBsXKvHLgCt7PuWIo1NyeVgFjlGBN9cC~L8Esxcy-iC0aDfJ2nWi7kMBPfHRVSvSFvu5jJVMjZrnwZRPI9Hrmj1VuBIbuV4SU3PZzHM5j~42SJkng8qVqfXb87KOclDpQHBtHRZiDlSLCFNokyUE3Lgmr2Uy03Gu4mKNTIKilz4h-luOgXCb3qt7IgNipqwVAb~YGQueaO3MsQX~qe07VQXoITkVmTdnod12T2au0APzzX25WZeTnJfGYZiGJQ__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
![A 22-year-old woman presented with fatigue and leukocytosis without organomegaly and a referral diagnosis of chronic myeloproliferative neoplasm without BCR::ABL1 translocation or JAK2 mutation. Complete blood count showed leukocytosis (white blood cell [WBC], 21.8 × 109/L), anemia (hemoglobin, 11.1 gm/dL), and thrombocytopenia (platelets, 114 × 109/L) with neutrophilia (15.9 × 109/L), eosinophilia (1.74 × 109/L), and rare circulating blasts. Bone marrow (BM) biopsy was hypercellular (∼100%) with myeloid hyperplasia, atypical megakaryocytic hyperplasia, and clusters of foamy histiocytes (panel A, ×400, hematoxylin-eosin stain) highlighted with periodic acid–Schiff stain with fast green counterstain (panel B, ×400). BM smears showed left-shifted myeloid hyperplasia with numerous pseudo-Gaucher cells/sea blue histiocytes with abundant blue and variably lamellar cytoplasm (panel C; ×1000, Wright-Giemsa). Karyotyping detected a t(5;12) (panel D), and fluorescence in situ hybridization confirmed the presence of PDGFRB (panel E) and ETV6 rearrangement in 78% of analyzed cells. The patient was treated with imatinib (400 mg daily) and achieved remission with a WBC of 8.9 × 109/L at 1-month follow-up.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/140/6/10.1182_blood.2022016602/3/m_bloodbld2022016602f1.png?Expires=1765011374&Signature=10HiKovVSqjcaW4D3L~TyJokASKNLHIcL6tBr4BGJjgJAaiMV1m7NuYuMFpTIsI7D18JeW9GzsUfqmOdIrw2Thlwbw~g86j6Rb7PUicSVlY7Qk3HB98DZZ05-wWQGqN4SdwpZxtR3RKtoQVrpbYWNhBdJ-y0gjOAK5EQps55QhwBnttHglgY7uMiiDcp5v7mGK5cTP2sSt79rScVMTkF0C7LQG3PBjJOI6bN4eQ1t41Rbgj3XcNbkP~5uCCJmO7Dqboc~lMm06w3OCdNDHSpyGdKYisAREA7LJxa9Y4HFsPZS5qEYZKDW31DmpJa8DA4VEtHkcEPTs~CCq9KZSMfPA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)