Myeloproliferative neoplasms (MPN) are a heterogeneous group of hematological disorders presenting with an increased proliferation in one or several hematological cell lines. Renal manifestations of MPN have not been fully characterized so far. To morphologically assess the potential renal involvement in MPN patients, we analyzed histomorphological findings of a post-mortem cohort (n = 57) with a disease history of Philadelphia-negative MPN including polycythaemia vera, primary myelofibrosis, essential thrombocythemia, or chronic myelomonocytic leukemia (CMML). Seven (12.2%) patients presented with a pattern of diffuse glomerulosclerosis not attributable to diabetic or hypertensive nephropathy. Weak C4d staining suggestive for chronic thrombotic microangiopathy (TMA) was observed in 4/7 cases. Glomerulonephritis was excluded by light microscopy and immunohistochemistry. Patients with a pattern of diffuse glomerulosclerosis did not differ from the rest of the cohort regarding MPN subtype, disease duration, age, or sex. No significant proteinuria had been observed before death. Further findings attributed to MPNs were extramedullary hematopoiesis (n = 5; 8.8%) and tumor involvement in advanced disease (n = 4; 7.0%). Other common findings included arteriolosclerosis (n = 18; 31.6%) and signs of shock (n = 8; 14.0%). To our knowledge, this study is so far the largest investigating renal findings in MPN patients. There may be a causal relationship between idiopathic diffuse glomerular sclerosis and MPN, although its clinical significance and pathophysiology remain uncertain with TMA probably being relevant in a subgroup of cases. Our findings demonstrate the spectrum of renal findings in MPN from early to terminal disease of which hematologists should be aware of in daily clinical practice.

骨髓增生性肿瘤（MPN）是一组异质性血液疾病，表现为一种或多种血液细胞系增殖增加。迄今为止，MPN 的肾脏表现尚未完全明确。为了从形态学上评估 MPN 患者潜在的肾脏受累，我们分析了具有费城阴性 MPN 病史的死后队列 (n = 57) 的组织形态学结果，包括真性红细胞增多症、原发性骨髓纤维化、原发性血小板增多症或慢性粒单核细胞白血病。 CMML）。七名 (12.2%) 患者出现弥漫性肾小球硬化，但并非糖尿病或高血压肾病。在 4/7 的病例中观察到提示慢性血栓性微血管病 (TMA) 的弱 C4d 染色。通过光学显微镜和免疫组织化学排除肾小球肾炎。患有弥漫性肾小球硬化症的患者在 MPN 亚型、病程、年龄或性别方面与其他队列患者没有差异。死亡前未观察到明显的蛋白尿。归因于 MPN 的进一步发现包括髓外造血（n = 5；8.8%）和晚期疾病中的肿瘤受累（n = 4；7.0%）。其他常见的发现包括动脉硬化（n = 18；31.6%）和休克迹象（n = 8；14.0%）。据我们所知，这项研究是迄今为止最大规模的 MPN 患者肾脏发现调查。特发性弥漫性肾小球硬化症与 MPN 之间可能存在因果关系，尽管其临床意义和病理生理学仍不确定，TMA 可能与一个亚组病例有关。 我们的研究结果证明了 MPN 从早期到晚期的肾脏表现，血液学家在日常临床实践中应注意这一点。