Myeloid/lymphoid neoplasm with eosinophilia and rearrangement of PDGFRA presenting as myeloid sarcoma

[摘要] A 32-year-old male patient with no significant past medical historypresented with fatigue and left groin lymphadenopathy. The left groinlymph node was excised and measured 2.0 × 1.4 × 1.1 cm. On histologicexamination, the lymph node architecture was effaced by atypical cellswith intermediate to large nuclei, round nuclear contours, vesicularchromatin, prominent nucleoli, and moderate basophilic cytoplasmadmixed with abundant eosinophils (Figure 1, top left, objective40×). By immunohistochemistry, the neoplastic cells express CD13(subset), CD33 (weak), CD34 (weak), CD45, CD68/PG-M1 (subset),CD71 (top right, objective 40×), CD117 (subset), CD123 (weak), andHemoglobin A (subset). Given the extensive eosinophilic infiltration,FISH analysis for PDGFRA (4q12) and PDGFRB (5q33) was performed.A rearrangement of the PDGFRA (4q12) gene region with loss of5′ PDGFRA and retention of 3′ oncogenic portion was identified in63% of nuclei (Figure 1. bottom left, PDGFRA 5′(G) / 3′(R) [4q12],arrows indicate disruption of PDGFRA).