PMC4697351_01
Lymph node (LN) and bone marrow (BM) immunohistochemistry. (A) Myeloid sarcoma in an inguinal LN showing increased immature cells with less cytoplasms, round nuclei, and distinct prominent nucleoli (Hematoxylin & Eosin [H&E] stain, x400); (B) Increased immature cells in an inguinal LN positive for myeloperoxidase (x400) and (C) CD117 (x400); (D) Diluted BM aspiration showing normal hematopoietic cells (Wright stain, x1,000); (E) BM biopsy showing cellularity of nearly 100% (H&E stain, x400); (F) Megakaryocytes positive for CD61 without proliferation and atypia (x200); (G) BM biopsy showing grade 2 myelofibrosis (on a 0-3 scale), with diffuse and dense reticulin fibers (Reticulin stain, x400); (H) focal bundles of collagen fibers (Masson Trichrome stain, x400).
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F1
CD117 (Fig. 1A-C). CBC revealed 5.8x109/L leukocytes, 7.7 g/dL hemoglobin, and 130x109/L platelets, and a PB smear showed leukoerythroblastic reaction (nucleated red blood cell [RBC]: 3/100 white blood cell [WBC]; metamyelocytes: 2%). BM aspiration indicated a normal myeloid:erythroid ratio and 3.2% eosinophils without myelodysplasia, and a biopsy confirmed hyperplasia and myelofibrosis without megakaryocytic proliferation and atypia (Fig. 1D-H).
The t(8;9)(p22;p24) translocations and PCM1-JAK2 fusion gene. (A) Karyogram of bone marrow showing 46,XY,t(8;9)(p22;p24)[20]; (B) Reverse transcription-PCR product of the PCM1-JAK2 gene from bone marrow; (C) Genetic sequence and schematic representation of the chimeric PCM1-JAK2 gene.
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F2
The BM karyotype was 46,XY,t(8;9)(p22;p24)[20] (Fig. 2A), and reverse-transcription (RT)-PCR was performed with the following primers which we designed: PCM1 forward 5'-TAGTGCTGCCCATAAGGAGTC-3' and JAK2 reverse 5'-AGCGAACAGTTTCCATCTGGT-3'. Sanger sequencing revealed an in-frame fusion between exon 36 of PCM1 and exon 9 of JAK2 (Fig. 2B, C), which were shown in previous reports.