Ga68-DOTA Peptide PET/CT to Detect Occult Mesenchymal Tumor-Inducing Osteomalacia: A Case Series of Three Patients

Abstract

Tumor-induced osteomalacia (TIO) is a rare disease that manifests with paraneoplasic syndrome and overproduction of fibroblast growth factor 23 (FGF23), leading to renal phosphate wasting and hyperphosphaturia, eventually leading to acquired hypophosphatemic osteomalacia. Diagnosis of this disease is often challenging because of the small size of the lesion, which can be localized in bone or soft tissue anywhere in the body. Detecting these occult mesenchymal tumors (OMT) is of great importance as they are potentially curable after tumor resection. The purpose of this case series is to provide some insight into the diagnosis and localization of OMT associated with osteomalacia, particularly using functional imaging with Ga68-DOTA peptide PET/CT scans.

68Ga-DOTATATE for Tumor Localization in Tumor-Induced Osteomalacia

“…Jadhav et al also used 99 Tc-HYNIC-Octreoscan, which had 100% sensitivity and specificity in all six patients undergoing this imaging (4). A recent case series also described the successful use of 68 Ga-DOTA peptide PET/CT imaging in localizing PMT tumors in all three of three patients presenting with TIO (13). 68 Ga-DOTANOC has been evaluated in one study of 10 TIO patients showing a sensitivity and specificity of 90% (9).…”

Oncogenic osteomalacia: role of Ga-68 DOTANOC PET/CT scan in identifying the culprit lesion and its management

“…However, the data available in the literature with the SSTR PET/CT-based imaging in these tumours are limited ( Table 2). [18][19][20][21][22][23][24][25][26] Among the variety of somatostatin analogues, most commonly used for imaging are 68 Ga-DOTA 0 -Ty 3 octreotate (DOTATATE), 68 Ga-DOTA 0 -Ty 3 octreotide (DOTATOC) and 68 Ga-DOTA 0 -NaI 3 octreotide (DOTANOC) with variable SSTR subtype specificity. The specific modification of octreotide at Position 3 in 68 Ga-DOTANOC leads to higher affinity to SSTR-2 and SSTR-5.…”

Phosphaturic mesenchymal tumor: Case report

“…Although PMTs manifest ultrastructural features of neuroendocrine tumors, they typically lack the immunohistochemical markers of neurosecretory tumors that typically consist of S-100, neuron-specific enolase, chromogranin, and synaptophysin markers. In a systematic process following GaTate testing for localization, systemic venous sampling should be recommended for proper confirmatory testing of serum FGF23 levels, followed by functional MR imaging for direct tumor characterization [9], [10], [11]. In contrast, the currently presented case never required these methods of localization due to previous identification and localization on prior imaging with symptom onset being coincidentally near the time of identification.…”

“…The previous challenge of this localization existed with the PET tracer fluoro-2-deoxy-d-glucose and its relatively low sensitivity and specificity for the overall detection of neuroendocrine tumors and PMTs. This dilemma has called for better-established methods leading to the advancement of DOTA chelators and a variety of newer-generation somatostatin analogs; all of which have shown a higher radiotracer affinity compared to conventional octreotide imaging [8], [9], [10]. The clinical choice of a particular analog is often driven by local availability, with studies directing only subtle differences in clinical utility.…”