A 48-year-old woman whose progressive bone pain and lower limb weakness were traced to a rare hormone-secreting tumor has undergone an unusual minimally invasive treatment: CT-guided microwave ablation of a tumor embedded in her acetabulum, the socket of the hip joint. The case, published as a case report in BMC Surgery, describes how ablation of a single lesion normalized her serum phosphate within 13 days, even though imaging had revealed several other suspicious lesions that were never treated.
Tumor-induced osteomalacia is a rare paraneoplastic syndrome caused by phosphaturic mesenchymal tumors, which secrete fibroblast growth factor-23. This hormone drives phosphate loss through the kidneys, producing severe hypophosphatemia and the hallmark symptoms of bone pain and muscle weakness. The tumors are often small and anatomically difficult to localize, and surgical resection may be unfeasible when they sit in deep or complex locations such as the pelvis.
Diagnostic imaging with 68Ga-DOTATATE PET/CT identified multiple DOTATATE-avid lesions in this patient, three of which were most prominent: one in the left acetabulum with an SUVmax of 13.16, one in the left femoral head with an SUVmax of 7.71, and one at the right femur lesser trochanter with an SUVmax of 7.09. Biopsy of the acetabular lesion confirmed a phosphaturic mesenchymal tumor, showing strong SSTR2 immunohistochemical positivity and a Ki-67 index of 2%.
The complex anatomy of the acetabulum precluded safe surgical resection, so the team turned to percutaneous microwave ablation. The procedure was performed under CT guidance, with pre-procedural planning based on the 68Ga-DOTATATE PET/CT scan. Only the acetabular lesion was ablated; the femoral head and lesser trochanter lesions were left untreated.
The biochemical response was rapid. Serum phosphate normalized by day 13 after the procedure. Follow-up PET/CT then produced a notable observation: SUVmax fell not only at the treated acetabular site, dropping to 1.08, but also at the untreated lesions, falling to 4.04 in the femoral head and 5.21 at the lesser trochanter.
The report also documents the recovery trajectory in detail. Transient exacerbation of bone pain occurred during the first week after ablation. A surge in bone turnover markers, including P1NP and β-CrossLaps, peaked at 2.7 months. Both the pain flare and the marker surge resolved by 8.7 months, with sustained biochemical improvement at that point.
The authors draw a careful conclusion from the imaging pattern. Because the untreated DOTATATE-avid lesions were not histologically confirmed, and sustained biochemical remission followed ablation of the single proven tumor, they caution that not all such lesions should be assumed to be true PMT metastases. Biopsy confirmation is essential before treating additional sites, they write, since DOTATATE uptake alone does not establish tumor identity.
As a single case report, the findings cannot establish efficacy across a population, and the authors frame microwave ablation as a suggestion rather than a proven standard. Still, the case suggests that MWA may be a feasible and potentially effective minimally invasive alternative in selected patients with acetabular PMTs for whom surgical resection is associated with substantial morbidity. For patients whose tumors sit where the scalpel cannot safely reach, the report offers a documented example of biochemical cure achieved through a needle-based thermal technique.
Subject of Research: Microwave ablation of a phosphaturic mesenchymal tumor causing tumor-induced osteomalacia
Article Title: Percutaneous microwave ablation of an acetabular phosphaturic mesenchymal tumor causing tumor-induced osteomalacia: a case report
Article References: Ruan, D., Li, Y., Yu, L., Wu, Z., Cai, J., & Sun, L. (2026). Percutaneous microwave ablation of an acetabular phosphaturic mesenchymal tumor causing tumor-induced osteomalacia: a case report. BMC Surgery. https://doi.org/10.1186/s12893-026-04321-0
Image Credits: AI Generated
DOI: 10.1186/s12893-026-04321-0
Keywords: tumor-induced osteomalacia, phosphaturic mesenchymal tumor, microwave ablation, FGF23, hypophosphatemia, 68Ga-DOTATATE PET/CT, acetabulum, interventional radiology, case report, bone pain, Percutaneous, microwave
News Source: Nathaniel Bowman. (October 30, 2026). Microwave ablation of an acetabular tumor restores phosphate in osteomalacia case. Scienmag.
