177Lu-DOTATATE PRRT in Recurrent Skull-Base Phosphaturic Mesenchymal Tumor Causing Osteomalacia: A Potential Application of PRRT Beyond Neuroendocrine Tumors

The potential of peptide receptor radionuclide therapy (PRRT) is described in a case of recurrent inoperable phosphaturic mesenchymal tumor causing osteomalacia in the left basiocciput, for which the patient had undergone surgery twice previously. After one cycle of PRRT, there was good symptomatic improvement, with a modest reduction in uptake on both 68Ga-DOTATATE PET/CT and 18F-FDG PET/CT suggesting a favorable response. Hence, treatment with a second cycle was considered. Being somatostatin receptor–avid, this rare group of tumors when inoperable or recurrent may potentially be targeted with PRRT. Well-tolerated and noninvasive, PRRT could evolve as a promising targeted treatment approach in this clinical setting. In summary, tumor-induced osteomalacia with 68Ga-DOTATATE–avid inoperable or recurrent tumor can be considered a potential clinical application for PRRT beyond neuroendocrine tumors.