A Rare Case: Solitary Fibrous Tumor With Widespread Metastasis on [68Ga]Ga-DOTATATE PET/CT

Abstract

Background Intracranial solitary fibrous tumor (SFT) are rare pericyte neoplasms arising from the meninges. They resemble meningiomas due to their location and are hyperdense on CT. Therefore, they may be a source of pitfalls. However, unlike meningiomas, there is no calcification or hyperostosis of the adjacent bone. We report a rare case of metastatic SFT presenting with masses in the left cerebral hemisphere, both lungs, left kidney, C4 vertebra, and scalp with intense radiotracer uptake. Case presentation A 66-year-old male patient was referred to our center with intracranial masses initially diagnosed as meningiomas. The patient, who developed compression symptoms, underwent surgery for masses in the left cerebral hemisphere. According to WHO classification [1], the pathology revealed as high-risk (grade 3) SFT with high proliferative activity. Immunohistochemical findings: Bcl-2-124 (positive), CD34 (focal pale positive), CD99 (membranous positive), Ki67 (MIB1): %14, PHH3 (positive in 10 cells in per 10 high-power fields), STAT 6 (diffuse nuclear positive). And 10 mitoses were seen in per 10 high-power fields. Imaging results revealed extracranial metastases in addition to intracranial masses, both demonstrating intense radiotracer uptake. Conclusions Although SFTs can be confused with meningiomas based on imaging findings, distinguishing between the two is crucial due to the rarity, aggressive behavior, and potential for extracranial metastasis associated with SFTs. Ga-68 DOTA PET/CT offers significant contributions to the differential diagnosis of these two tumor types. However, it is known in the literature that meningiomas can also exhibit a high rate of DOTA uptake, and, although rare, extracranial metastases can exhibit DOTA positivity. Therefore, a holistic approach to evaluating radiologic, clinical, and histopathologic findings is necessary for definitive diagnosis, rather than relying solely on Ga-68 DOTA PET/CT findings. Furthermore, as seen in this rare case with limited therapeutic options, the high expression of somatostatin receptor raises the possibility of radiolabeled somatostatin analogs as a potential treatment option in the context of widespread metastatic disease.