Laboratory Assessment of Patients with Systemic Mastocytosis

儿童肥大细胞增多症的管理是一个挑战。关于临床和实验室检查结果以及骨髓评价的应用信息有限，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。关于儿童肥大细胞增多症的骨髓病理学资料很少。我们评估了世界卫生组织（WHO）诊断儿科患者全身性疾病的标准。通过组织病理学和免疫组织化学、流式细胞术和KIT突变分析对骨髓活检进行分析。对50例患者进行了完整的骨髓评价。7名儿童接受了重复手术。我们在活检中发现了独特的临床组织病理学特征。骨髓活检显示轻度非典型造血成熟，增加的造血细胞和细胞减少的一个子集的患者色素性荨麻疹，弥漫性皮肤肥大细胞增多症和惰性系统性肥大细胞增多症。细胞减少是最明显的那些与色素性荨麻疹。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血细胞生成素增加最高。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。本研究中患者的长期随访（中位数6.9年;范围1-25年）显示，所有患者均保持临床稳定，未进展为更具侵袭性的变异。我们的结论是世界卫生组织标准适用于诊断系统性肥大细胞增多症在儿科。

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.