Aggressive Behavior Predictors in Solitary Fibrous Tumor: Demographic, Clinical, and Histopathologic Characteristics of 81 Cases

Diagnosis and management of an extremely rare solitary fibrous tumor in the retropubic space of Retzius: A case report

INTRODUCTION AND IMPORTANCE

Solitary fibrous tumors (SFTs), rare mesenchymal tumors, occur in diverse locations. Retroperitoneal and pelvic SFTs are extremely uncommon, challenging to identify due to vague clinical and radiological features. We present a high-risk SFT case in the retropubic Retzius space.

CASE PRESENTATION

A 56-year-old woman with diabetes and bronchial carcinoid tumor had abdominal pain. Physical exam revealed hypogastric and pelvic masses. MRI showed a 16.5x12x8cm mass near the bladder. Initial laparotomy deemed it unresectable; biopsy indicated grade 2 FNCLCC mesenchymal tumor. In a second surgery, a 20 cm mass was successfully removed from the Retzius space. Histopathology confirmed SFT. Due to vaginal involvement, adjuvant radiotherapy was given. After 12 months, clinical and radiological follow-up showed remission. Unusual SFT location and successful treatment highlight the importance of comprehensive assessment and multidisciplinary approach in managing these rare tumors.

CLINICAL DISCUSSION

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms, often found in extremities but seldom in the abdomen. Diagnosis is challenging due to vague symptoms and imaging. This case discusses an unusual SFT location in the pelvic space, requiring surgical removal. SFTs are typically benign but can be malignant, requiring wide resection and potential adjuvant therapy.

CONCLUSION

Diagnosing SFTs can be difficult because of their non-specific clinical and radiological characteristics, but imaging studies and biopsies can aid in the diagnosis. The preferred treatment for SFTs is surgical removal with clear margins, and regular follow-up is essential to watch for any signs of recurrence.

Solitary Fibrous Tumor of the Prostate Shown on FAPI PET/CT

ABSTRACT

Solitary fibrous tumors are fibroblast tumors that occur mainly in the peritoneum, extremities, and pleura. Here, we report the MRI, FDG PET/CT, and FAPI PET/CT findings of a rare prostate solitary fibrous tumor. A 57-year-old man was pathologically diagnosed with a solitary fibrous tumor. To detect any systemic metastases or other primary lesions, the patient underwent FDG PET/CT and FAPI PET/CT examination sequentially. Mild FDG uptake was observed in the primary prostatic lesion, but there was a significant uptake of FAPI in the prostate. This case highlighted that FAPI PET/CT may outperform FDG PET/CT in identifying solitary fibrous tumors.

Value of Cellular Components and Focal Dedifferentiation to Predict the Risk of Metastasis in a Benign-Appearing Extra-Meningeal Solitary Fibrous Tumor: An Original Series from a Tertiary Sarcoma Center

Histology has not been accepted as a valid predictor of the biological behavior of extra-meningeal solitary fibrous tumors (SFTs). Based on the lack of a histologic grading system, a risk stratification model is accepted by the WHO to predict the risk of metastasis; however, the model shows some limitations to predict the aggressive behavior of a low-risk/benign-appearing tumor. We conducted a retrospective study based on medical records of 51 primary extra-meningeal SFT patients treated surgically with a median follow-up of 60 months. Tumor size (p = 0.001), mitotic activity (p = 0.003), and cellular variants (p = 0.001) were statistically associated with the development of distant metastases. In cox regression analysis for metastasis outcome, a one-centimeter increment in tumor size enhanced the expected metastasis hazard by 21% during the follow-up time (HR = 1.21, CI 95% (1.08-1.35)), and each increase in the number of mitotic figures escalated the expected hazard of metastasis by 20% (HR = 1.2, CI 95% (1.06-1.34)). Recurrent SFTs presented with higher mitotic activity and increased the likelihood of distant metastasis (p = 0.003, HR = 12.68, CI 95% (2.31-69.5)). All SFTs with focal dedifferentiation developed metastases during follow-up. Our findings also revealed that assembling risk models based on a diagnostic biopsy underestimated the probability of developing metastasis in extra-meningeal SFTs.

Multidisciplinary treatment of giant presacral solitary fibrous tumour: a case report and literature review

Solitary fibrous tumours (SFTs) usually occur at the pleura. Extrapleural sites, particularly giant extrapleural solitary fibromas, are more rarely observed in the clinic, and the clinical diagnosis and treatment of this disease is a focus of attention. Herein, the case of a 43-year-old male patient with giant presacral SFT successfully treated by open surgery, and with a final diagnosis confirmed by postoperative pathology and immunohistochemistry, is reported. The patient was followed-up regularly during 5 years after surgery, with no obvious surgical complications, and no tumour recurrence noted on pelvic magnetic resonance imaging. This case provides clinical information that may help in the diagnosis and treatment of complex SFT.