2016年12月,一名62岁男子因全血细胞减少和白细胞分数异常被转诊至我院。骨髓抽吸显示原始细胞大量增殖(96%),具有丰富的髓过氧化物酶阴性嗜碱性颗粒。他被诊断出患有急性嗜碱性白血病,并开始对急性髓细胞性白血病进行适当的治疗。Blast细胞的BCR-ABL微小突变呈阳性,使用伊马替尼的化疗在第7天开始。治疗有效,在第30天达到完全缓解。原始细胞的超微结构特征在电子显微镜上显示典型的嗜碱性颗粒,具有高电子密度结构。然而,免疫组织化学分析为CD79a阳性,PAX5和TdT表达。检测免疫球蛋白重链和T细胞受体基因的重排,提示诊断费城染色体阳性急性淋巴细胞白血病(Ph+ALL)伴嗜碱性改变。患者继续接受伊马替尼联合方案治疗,以及脐带血移植。患者目前已实现无复发生存。这种情况代表了形态和分子状况之间的罕见分歧。
A 62-year-old man was referred to our hospital due to pancytopenia and abnormal leukocyte fraction in December 2016. Bone marrow aspiration showed a massive proliferation of blast cells (96%) with rich myeloperoxidase-negative basophilic granules. He was diagnosed with acute basophilic leukemia, and an appropriate treatment for acute myelogenous leukemia was initiated. Blast cells were positive for minor BCR-ABL mutations, and chemotherapy using imatinib was initiated on day 7. The treatment was effective and complete remission was achieved on day 30. The ultrastructural features of blast cells showed typical basophilic granules with high electron density structure on electron microscopy. However, immunohistochemical analysis were positive for CD79a, PAX5, and TdT expression. Rearrangements of immunoglobulin heavy chain and T-cell receptor genes were detected, prompting the diagnosis of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) with basophilic change. The patient continued to be treated with the imatinib combination regimen, as well as umbilical cord blood transplantation. The patient has currently achieved recurrence-free survival. This case represents a rare divergence between morphology and molecular condition.