磷酸盐尿性间叶肿瘤的临床及免疫组织化学特点分析

Clinical and immunohistopathologic study of phosphaturic mesenchymal tumor

目的探讨磷酸盐尿性间叶肿瘤（phosphaturic mesenchymal tumor, PMT）的临床特征及免疫组织化学表型。方法回顾性分析2008年7月至2017年9月北京协和医院206例PMT的临床病理资料及免疫组织化学表型，并复习相关文献。结果206例PMT患者男女比例1.1∶1.0，平均年龄42岁（范围13～70岁）。临床表现为不同程度的骨痛、乏力、活动受限，部分有身高变矮、胸廓变形、病理性骨折等。206例患者中，197例记录了术前骨软化症状持续时间（20 d至40年），症状平均持续时间5.7年。血生化检测显示低血磷，高尿磷，高碱性磷酸酶（ALP），而1，25（OH）2D3水平偏低。206例患者中190例有术前血磷结果，176例有术后血磷结果，175例有对应的手术前后血磷结果。手术前平均血磷浓度0.49 mmol/L，手术后平均血磷浓度0.92 mmol/L（P〈0.01）；术后2周内血磷恢复至正常值的有147例（84.0%，147/175），术后15 d血磷累积恢复率为79.6%；手术完全的PMT患者术后2周血磷累积恢复率为85.4%，手术不完全（肿瘤有残留）的PMT患者血磷累积恢复率约为21.1%（P〈0.01）。PMT发病部位最常见于下肢（55.8%，115/206），其次是头颈部（29.1%，60/206）。免疫组织化学染色结果显示，波形蛋白阳性率100.0%（166/166），神经元特异性烯醇化酶阳性率96.3%（133/138），CD56阳性率94.2%（162/172），成纤维细胞生长因子-23阳性率88.4%（114/129），CD68阳性率88.3%（91/103），D2-40阳性率70.9%（78/110），CD34阳性率23.1%（40/173），平滑肌肌动蛋白阳性率55.5%（81/146），bcl-2阳性率59.8%（101/169），CD99阳性率47.1%（75/159）。Ki-67阳性指数≤2%者占51.4%（92/179），3%～10%者占41.3%（74/179），〉10%者占7.2%（13/179）。结论PMT具有独特的临床及血生化特征，最常发生于下肢和头颈部；肿瘤细胞表达多种免疫组织化学标志物，提示具有多向分化潜能；临床与血生化表现以及免疫组织化学表型有助于PMT的正确诊断。

ObjectiveTo study the clinicopathological characteristics and immunohistochemical phenotype of phosphaturic mesenchymal tumor （PMT）.MethodsThe clinicopathological data and immunohistochemical profiles were obtained retrospectively from 206 patients diagnosed with PMT at Peking Union Medical College Hospital （PUMCH） during July 2008 to September 2017, with a review of literature.ResultsThe mean age of PMT patients was 42 years （range 13 to 70 years）, with a male to female ratio of 1.1∶1.0. All patients presented with different degree of bone pain, muscle weakness, shorten of stature, thoracic deformity and pathological fractures, with hypophosphatemia and high serum ALP. Phosphatemia returned to normal within 1 week after operation in all cases underwent complete tumor resection. The duration of osteomalacia before resection （documented in 197 cases） ranged from 20 days to 40 years （average 5.7 years）. The average blood phosphorus concentration raised from 0.49 mmol/L to 0.92 mmol/L before and after tumor resection （P〈0.01）, with 147 cases （84.0%, 147/175） returned to normal range within 2 weeks. The rate or blood phosphorus concentration recovery in 15 days after operation was 79.6% in average, displayed significant differences between patients with complete resection and those with partial resection （85.4% vs. 21.1%, P〈0.01）. PMT lesions mainly involved lower extremities （55.8%）, followed by head and neck （29.1%）. In immunohistochemical study, all cases were positive for vimentin （100.0%）, while most cases were positive for NSE （96.3%）, CD56 （94.2%）, FGF23（88.4%）, CD68 （88.3%）, D2-40 （70.9%）, CD34 （23.1%）, SMA （55.5%）, bcl-2 （59.8%） and CD99 （47.1%）. The Ki-67 positive index of tumor varied from less than 2% （51.4%）, 3% to 10% （41.3%） to 〉10% （7.2%）.ConclusionsPMT mainly occurs in lower limbs or head and neck, with unique clinical characteristics and blood biochemical indexes. The tumor expresses a variety of immunohistochemical markers, indicating the potential of multi-directional differentiation. Clinical profile, blood biochemistry testing and immunohistochemical phenotype is helpful for diagnosis of PMT.