Patil Madhuri D, Wangsiricharoen Sintawat, Lazar Alexander J, Moon Bryan, Madewell John E, Collins Michael T, Guise Theresa A
Division of Endocrinology and Metabolism, Baylor College of Medicine, Houston, TX 77030, United States.
Department of Pathology and Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States.
JBMR Plus. 2024 Nov 15;9(1):ziae145. doi: 10.1093/jbmrpl/ziae145. eCollection 2025 Jan.
Dysregulated FGF23 production is a demonstrated cause of hypophosphatemia and osteomalacia. Diseases associated with these conditions include phosphaturic mesenchymal tumor (PMT) causing tumor induced osteomalacia, various forms of rickets, and fibrous dysplasia (FD). Coexistence of 2 conditions that can increase FGF23 concentrations is rare. We report a case of a 79-yr-old man who presented with rib and right flank pain. Imaging revealed bone lesions in the right iliac wing, left supra-acetabular area, and L4 vertebral body. Biopsies showed a right iliac PMT and left supra-acetabular FD. Cryoablation of both lesions resolved the phosphaturia with normalization of phosphorus level. Coexistence of PMT and FD in this patient with hypophosphatemia raised questions about the source of the FGF23, meaning of coexistence of PMT and FD in the same patient and, about the nature of the third lesion in the L4 vertebral body. Using FGF23 mRNA chromogenic in situ hybridization, we identified the PMT, rather than the FD, as the source of FGF23. Lack of mutation in the PMT suggested it being independent of FD. Assessment by the intact FGF23: total FGF23 ratio as well as gallium-DOTATATE scan suggested that the vertebral body lesion could represent FD. Other than understanding difference in underlying molecular processing of FGF23 in PMT and FD, testing for mutations, imaging studies as well as in situ hybridization helped solve the questions arising from this unique case of coexistence of PMT and FD.
成纤维细胞生长因子23（FGF23）生成失调是低磷血症和骨软化症的一个已证实病因。与这些病症相关的疾病包括导致肿瘤性骨软化症的磷酸尿性间叶肿瘤（PMT）、各种形式的佝偻病以及骨纤维发育不良（FD）。两种可增加FGF23浓度的病症同时存在的情况较为罕见。我们报告一例79岁男性患者，其表现为肋骨和右胁腹疼痛。影像学检查显示右髂骨翼、左髋臼上区域和L4椎体有骨病变。活检显示右髂骨为PMT，左髋臼上为FD。对两个病变进行冷冻消融后，磷尿症得到缓解，磷水平恢复正常。该低磷血症患者同时存在PMT和FD，引发了关于FGF23来源、同一患者中PMT和FD同时存在的意义以及L4椎体第三个病变性质的问题。通过FGF23 mRNA显色原位杂交，我们确定PMT而非FD是FGF23的来源。PMT缺乏突变表明它与FD无关。通过完整FGF23与总FGF23比值评估以及镓-奥曲肽扫描表明椎体病变可能代表FD。除了了解PMT和FD中FGF23潜在分子加工的差异外，突变检测、影像学研究以及原位杂交有助于解决这例PMT和FD同时存在的独特病例所引发的问题。
