Laboratory Assessment of Patients with Systemic Mastocytosis

儿童肥大细胞增多症的治疗是一项挑战。关于临床和实验室结果的应用以及骨髓评估方面的信息有限，因为它们与医疗干预和预后有关。儿童肥大细胞增多症的诊断标准主要基于成人研究。关于肥大细胞增多症儿童的骨髓病理数据很少。我们评估了世界卫生组织(WHO)标准在儿科患者系统性疾病诊断中的应用。采用组织病理学、免疫组织化学、流式细胞仪和KIT突变分析等方法对骨髓活检标本进行分析。对50例患者进行了完整的骨髓检查。七名儿童接受了重复手术。我们在活检中确定了独特的临床组织病理学特征。骨髓活检显示轻度不典型的造血成熟、红血球增多和细胞减少，这些患者包括色素性荨麻疹、弥漫性皮肤肥大细胞增多症和惰性全身性肥大细胞增多症。细胞减少在色素性荨麻疹患者中最为明显。平均而言，弥漫性皮肤肥大细胞增多症或肥大细胞瘤患者的红细胞生成量最高。在该队列中没有外周血细胞减少、骨髓增生异常综合征、骨髓增生性肿瘤或白血病的证据。在这项研究中对患者的长期随访(中位数为6.9年；范围为1-25年)显示，所有患者临床上保持稳定，没有进展为更具侵袭性的变异。结论WHO标准适用于儿科系统性肥大细胞增多症的诊断。

The management of children with pediatric mastocytosis poses a challenge. There is a limited information as to the application of clinical and laboratory findings and bone marrow evaluation as they relate to medical intervention and prognosis. The diagnostic criteria for pediatric mastocytosis are largely based on adult studies. There is very little data about bone marrow pathology in children with mastocytosis. We evaluated the use of the World Health Organization (WHO) criteria for the diagnosis of systemic disease in pediatric patients. Bone marrow biopsies were analyzed by histopathology and immunohistochemistry, flow cytometry and KIT mutational analysis. Complete bone marrow evaluations were performed in 50 cases. Seven children had repeat procedures. We identified unique clinico-histopathological features within the biopsies. Bone marrow biopsies displayed mildly atypical hematopoietic maturation, increased hematogones and hypocellularity in a sub-set of patients with urticaria pigmentosa, diffuse cutaneous mastocytosis and indolent systemic mastocytosis. Hypocellularity was most pronounced in those with urticaria pigmentosa. Hematogone increases were highest, on average, in patients with diffuse cutaneous mastocytosis or mastocytomas. There was no evidence of peripheral blood cytopenias, myelodysplastic syndrome, myeloproliferative neoplasm or leukaemia within this cohort. Long-term follow-up of patients within this study (median 6.9 years; range 1-25 years) showed that all patients remained clinically stable without progression to a more aggressive variant. We conclude that the WHO criteria are applicable for the diagnosis of systemic mastocytosis in pediatrics.