Li Jing, Huang Yuanyuan, Yang Fuzhou, Zhang Qi, Chen Decai, Wang Qin
Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu.
Department of Nuclear Medicine, Yaan People's Hospital, Yaan, Sichuan Province, China.
Medicine (Baltimore). 2018 Dec;97(52):e13849. doi: 10.1097/MD.0000000000013849.
Tumor-induced osteomalacia (TIO) is a rare, paraneoplastic syndrome featured with fibroblast growth factor 23 (FGF23) secretion primarily by benign mesenchymal tumors and sometimes by malignancies. TIO diagnosis and treatment is often delayed because TIO usually has nonspecific generalized bone pain and weakness, and location of TIO tumor is quite challenging. Very few TIO caused by sinonasal hemangiopericytoma have been reported in the literature.
A 40-year-old Chinese woman presented with diffuse bone pain for more than 1 year. Laboratory examination showed hypophosphatemia, hyperphosphaturia, hypocalcemia, an elevated serum alkaline phosphatase (ALP) level and bone-specific ALP level. Imaging studies revealed low bone mineral density (BMD) and multiple pseudofractures at the ribs. F-18 fluorodeoxyglucose positron emission tomography was negative in searching for tumors. Because no tumor was located, the patient was treated with oral phosphate, calcium, and alfacalcidol, and achieved great relief in her symptoms and improvement in BMD. Six years later, the patient had breast cancer surgery and received chemotherapy, and still had hypophosphatemia. During this time, nasopharyngo-fiberscope showed nasal mass in her left nasal cavity. Then she had her nasal polyps removed and surprisingly the serum phosphate became normal.
The patient had the nasal mass resected, and pathological diagnosis of the nasal mass was sinonasal hemangiopericytoma. Immunohistochemical analysis was positive for FGF23. Thus the final diagnosis was osteomalacia induced by sinonasal hemangiopericytoma. Phosphate supplementation and alfacalcidol were discontinued.
The patient had normal serum phosphate after 6-month follow-up.
By presenting this case, we hope to remind clinicians that in patients with osteomalacia with undetermined reason and intranasal polypoid mass, sinonasal hemangiopericytoma should be suspected.
肿瘤诱导的骨软化症（TIO）是一种罕见的副肿瘤综合征，其特征是主要由良性间充质肿瘤分泌成纤维细胞生长因子23（FGF23），有时也由恶性肿瘤分泌。TIO的诊断和治疗常常延迟，因为TIO通常有非特异性的全身性骨痛和乏力，且TIO肿瘤的定位颇具挑战性。文献中报道的由鼻窦血管外皮细胞瘤引起的TIO非常少。
一名40岁中国女性出现弥漫性骨痛1年多。实验室检查显示低磷血症、高磷尿症、低钙血症、血清碱性磷酸酶（ALP）水平和骨特异性ALP水平升高。影像学研究显示骨密度低（BMD）以及肋骨多处假骨折。F-18氟脱氧葡萄糖正电子发射断层扫描在寻找肿瘤方面呈阴性。由于未找到肿瘤，患者接受口服磷酸盐、钙和阿法骨化醇治疗，症状得到极大缓解，骨密度有所改善。6年后，患者接受了乳腺癌手术并接受化疗，但仍有低磷血症。在此期间，鼻咽喉纤维镜检查显示其左鼻腔有肿物。随后她切除了鼻息肉，令人惊讶的是血清磷酸盐恢复正常。
患者切除了鼻腔肿物，鼻腔肿物的病理诊断为鼻窦血管外皮细胞瘤。免疫组化分析FGF23呈阳性。因此最终诊断为鼻窦血管外皮细胞瘤诱发的骨软化症。停止补充磷酸盐和阿法骨化醇。
6个月随访后患者血清磷酸盐恢复正常。
通过展示该病例，我们希望提醒临床医生，对于原因不明的骨软化症且伴有鼻内息肉样肿物的患者，应怀疑鼻窦血管外皮细胞瘤。
