#00064323

A 38-year-old male was readmitted for profound afebrile leukocytosis 15 days after an uneventful inguinal hernia repair surgery.  The CBC on admission showed hyperleukocytosis (105 K/uL) with left-shifted granulocytes (granulocytes 76%), anemia (Hgb 7.6 g/dL), and thrombocytopenia (52 K/uL).  He was afebrile with splenomegaly. The bone marrow aspirate shows profound left-shifted granulocyte hyperplasia (M/E: 15.2), numerous eosinophil precursors, mild (1+) dyspoiesis, and low blast (1%) (Panel A).  The trephine biopsy showed hypercellularity (Panel B) with numerous eosinophils and focal necrosis. Multiple large, bright-red hexagonal or diamond-shaped crystals consistent with Charcot-Leyden crystals were identified in areas of necrosis (Panel C-D).  Chronic myeloid leukemia was ruled out with the absence of t(9;22)(BCR-ABL) by FISH and real-time PCR.  The urgent FISH for PDGFRA, PDGFRB, FGFR1, and JAK2 rearrangement revealed the presence of PDGFRB rearrangement in 54% of the leukocytes analyzed.  The final diagnosis of myeloid neoplasm with eosinophilia and rearrangement of PDGFRB (MNEo-PDGFRB) was made. The patient was initially treated with hydroxyurea and followed with imatinib. His blood counts were starting to normalize. Charcot-Leyden crystals are galectins and are occasionally found in myeloid neoplasm stained by H&E. Our case is the first to report Charcot-Leyden crystals in MNEo-PDGFRB.

Panel A. Left-shifted hypergranulopoiesis with eosinophilia and mild dyserythropoiesis (Wright-Giemsa, 100X oil).

Panel B. Hypercellular (100%) marrow with hypergranulopoiesis, eosinophilia, and focal necrosis (H&E, 20X).

Panel C. Hypercellular (100%) with viable hypergranulopoiesis with eosinophilia (H&E,100X).

Panel D. Charcot-Leyden crystals are present intracellularly and extracellularly in the necrosis (H&E, 50X).