Purpose To study the clinicopathological features of the phosphaturic mesenchymal tumors. Methods The clinicopatho-logical data, histology and immunohistochemical findings of 12 cases of phosphaturic mesenchymal tumors were retrospectively analyzed with review of the relevant literature. Results Among the 12 patients studied, 8 were males and 4 were females. Their age at the time of operation ranged from 23 to 63 years (mean=40. 5 years). The duration of symptoms ranged from 1 to 14 years (mean =5. 6 years) . A history of long-standing bone pain, arthralgia, limitation in movement, accompanied with hypophosphatemia and hyperphos-phaturia were present in all cases. The tumors size ranged from 1 to 7. 5 cm ( mean size=2. 7 cm) . The tumors were primarily com-posed of spindle cells, and were accompanied with osteoclast-like giant cells partly. Their background were rich in blood vessels. In addition, there were scattered tufed thick vascular anomaly, thin vascular, islands of mature adipocytes and chondroid cells. In 7 of the 12 cases, there were dystrophic calcification in an unusual flocculent. Spindle epithelium were noted in 2 cases. Mitotic figures were rare in 10 cases. In 2 of the 12 cases however, mitotic figures were commonly encountered, and in 1 of the 2 cases, heterotypic cells were notablely observed as well. On immunohistochemical study, the tumor cells were all positive for vimentin and CD56. The positivi-ty for NSE, CD99, BCL-2 in 11, 8 and 7 cases were expressed in 12 cases. In 4 and 6 of the 12 cases, CD34 and SMA were positive in various degree. Ki-67 proliferation index were less than 5% in 10 cases, and 10% and 25% in 2 cases. The duration of follow-up ranged from 2 to 108 months ( mean=22 months) . 2 cases were recurred at 72 and 84 months after the operation, respectively. So far, the remaining 10 cases had no recurrence and metastasis. Conclusioin The phosphaturic mesenchymal tumors are either benign or low-grade malignant. Their histomorphology are multivariable and short of specificity. It is important to make the correct diagnosis in combination with their common features and clinical datas.