Retroperitoneal Pelvic Solitary Fibrous Tumor With High Tracer Uptake in 68Ga-DOTATOC PET/CT

Abstract

We report the case of a 27-year-old woman referred to our department for the characterization of a 7 × 6-cm left ischio-anal fossa mass by Ga-DOTATOC PET/CT. Several diagnoses were previously mentioned, in particular, myxoid sarcoma but also pelvic paraganglioma. Urinary methoxylated derivates and blood chromogranin A tests were negative. PET/CT showed a high Ga-DOTATOC uptake of the mass that was strongly consistent with paraganglioma diagnosis. Histopathological analysis surprisingly revealed a solitary fibrous tumor without aggressive criteria.

Incidental Finding of a Parotid Basal Cell Adenoma With High Tracer Uptake on 68Ga-DOTATOC PET/CT

“…Indeed, several rare tumors could lead to potential pitfalls in 68 Ga-DOTATOC. 7 Concerning benign tumors of the salivary gland, incidental uptake has already been described in the literature for pleomorphic adenomas 8 due to an overexpression of somatostatin receptors on their surface. Nevertheless, the mechanism is less well-explained for BCA, especially as some reports suggested their absence of neuropeptide expression, contrary to Whartin tumors or pleiomorphic adenomas that are not developed from the same original cell.…”

“…Most of them are well known by nuclear physicians (eg, pancreatic uncinated process, inflammation, osteoblastic activity), 5,6 but the presence of an abnormal uptake in an unusual area should lead to caution regarding the PET/CT interpretation. Indeed, several rare tumors could lead to potential pitfalls in 68 Ga-DOTATOC 7 . Concerning benign tumors of the salivary gland, incidental uptake has already been described in the literature for pleomorphic adenomas 8 due to an overexpression of somatostatin receptors on their surface.…”

68Ga-DOTATOC PET/CT Imaging of a Muscular Solitary Fibrous Tumor

“…Excision was complete and 1 year postoperatively; MRI showed no sign of local recurrency. Very few cases of SFTs showing either high uptake in 68 Ga-DOTA-peptide PET/CT or in 111 In-pentetrotide scan have been reported in various locations: 5 of the pleura, 1 the most frequent localization of SFTs, and others in nasopharynx, 2 in the retroperitoneal pelvic region, 3 intracranial, 4 and one last with multiple liver and bone metastases 5 . Histopathological analysis reported a tumor measuring 8 × 5.5 cm.…”

“…Several liver metastases and one left pleural metastasis were also visualized on 68 Ga-DOTATOC PET/CT with high intensity uptake. Fused 111 In-pentetreotide, In-pentetrotide scan have been reported in various locations: 5 of the pleura, 1 the most frequent localization of SFTs, and others in nasopharynx, 2 in the retroperitoneal pelvic region, 3 intracranial, 4 and one last with multiple liver and bone metastases. 5 Histopathological analysis reported a tumor measuring 8 Â 5.5 cm.…”

Abdominopelvic Hemangiopericytoma Mimicking Neuroendocrine Tumor on 68Ga-DOTANOC PET/CT

“…Solitary fibrous tumors have shown SSTR expression when imaged using 68 Ga-DOTA peptides. 68 Ga-DOTATATE avidity has been reported in a case of nasopharyngeal SFT, 7 a case of pulmonary metastasis of an intracranial hemangiopericytoma, 8 a case of retroperitoneal pelvic SFT, 9 and a case of intracranial hemangiopericytoma 10 . 68 Ga-DOTATOC avidity has been demonstrated in 5 cases of pleural SFT 11 .…”