A solitary fibrous tumor arising in the parapharyngeal space, with MRI and FDG-PET findings

Solitary fibrous tumor of the parapharyngeal space: report of 2 cases and a literature review

The solitary fibrous tumor (SFT) is usually described as a lesion arising from the pleura. Rarely, it has been described in the parapharyngeal space (PS). This study aims to report two cases of SFT in the PS and to perform a literature review on this topic. Two patients undergoing surgical resection of a SFT in the PS, were reported. A literature review on SFT of the PS, was also performed. Two patients were analyzed. Both patients underwent surgical resection, followed by adjuvant radiotherapy, for SFT arising from the PS. The postoperative course was uneventful and both patients recovered well after the procedure. No recurrences were diagnosed during the followup. SFT of the PS is an infrequent entity. Surgical resection is the most used treatment, and adjuvant radiation should be considered in patients with recurrence risk factors or distant metastases.

The Natural History of Parapharyngeal Solitary Fibrous Tumor/Hemangiopericytoma: A Case Report

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is extremely rare, and most of them are immediately treated for radical resection. However, the information concerning its natural history remains unclear. In this report, we presented a patient with parapharyngeal SFT/HPC, who was not immediately treated with surgical resection at first diagnosis. After approximately 3 years, the tumor volume doubling time (TVDT) and specific growth rate (SGR) could be measured through 3 serial magnetic resonance imagings. The TVDTs in the early and late pretreatment stages were 350 and 180 days, respectively, while the SGRs were 0.002 and 0.003, respectively. The growth rate of this disease entity is generally slow and may accelerate in the disease process.

Integrally calcified solitary fibrous tumor in the retroperitoneum: a case report and review of the literature

Solitary fibrous tumor (SFT) is a rare stromal neoplasm and usually occurs in the thoracic cavity. We here report a case of retroperitoneal SFT with prominent calcification. A 64-year-old man presented with an incidentally detected retroperitoneal mass in the right upper abdomen. Imaging tests indicated an integrally calcified mass. The lesion was observed for 2 years and laparoscopically resected according to the patient's wish. Microscopically, the mass was mostly occupied by calcification and proliferous spindle cells were scattered with positive CD34 expression. We diagnosed morphologically benign SFT and the patient remained disease-free 1 year after the excision. There has been no report of such integrally calcified SFT. Retroperitoneal SFT is difficult to make a preoperative diagnosis, and careful follow-up after the excision is recommended because morphological malignancy does not always correspond to clinical malignancy.

Giant Leiomyoma Arising from the Mediastinal Pleura: A Case Report

This report presents a rare case involving a patient with a giant leiomyoma originating from the mediastinal pleura. The patient underwent a medical examination, and chest radiography revealed a giant tumor. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a well demarcated, heterogeneous mass which seemed to originate from the posterior mediastinum. Positron emission tomography (PET) showed the uptake of this tumor with a standardized uptake value of 4.9. We suspected that this tumor was a solitary fibrous tumor, and the patient underwent a surgical resection. Intraoperative exploration revealed a well-encapsulated tumor measuring 15 × 11 cm that appeared to originate from the mediastinal pleura. Immunohistochemical findings revealed a benign leiomyoma. We finally diagnosed the patient with a mediastinal leiomyoma. The present report describes CT, MRI, and PET findings of leiomyoma, and presents a review of relevant literature.

(18)F-FDG PET/CT imaging of malignant hepatic solitary fibrous tumor

Solitary fibrous tumor of the liver was rarely documented. F-FDG PET/CT imaging of malignant hepatic solitary fibrous tumor in a 49-year-old male patient was reported. The multifocal hepatic lesions demonstrated avid FDG uptake. FDG PET/CT might be potentially useful in the differentiation of benign and malignant solitary fibrous tumor.

Solitary fibrous tumor of the post-styloid parapharyngeal space

Solitary fibrous tumor (SFT) is a well-known tumor composed of spindle cells found most commonly in the pleura. Recently, accounts of their rare occurrence at other sites, including the head and neck area, have been reported. The parapharyngeal space is a rare location even for head and neck SFTs, and thus, could be confused with a variety of other tumors that can originate in this area. Here, we report a case of SFT originating from the post-styloid parapharyngeal space and discuss the possible differential diagnosis on radiographic findings.

MRI findings of solitary fibrous tumours in the head and neck region

OBJECTIVES

To analyse the MRI findings of solitary fibrous tumours in the head and neck region.

METHODS

We retrospectively reviewed MR images in eight patients with solitary fibrous tumours proven on histological examination. All the patients underwent conventional MRI, and four patients also underwent dynamic contrast-enhanced MRI and diffusion-weighted imaging in five cases. Image characteristics were analysed.

RESULTS

All lesions were found as solitary well-defined masses ranging in size from 1.9 to 6.8 cm (mean, 4.1 cm). They were mostly homogeneous and isointense to the muscle on T1 weighted images and heterogeneous and mildly hyperintense on T2 weighted images. After gadolinium administration, areas that were mildly hyperintense on T2 weighted images were strongly enhanced. They were mildly hyperintense on diffusion-weighted imaging. The average tumour-apparent diffusion coefficient values were 0.001 157 ± 0.000 304 9 mm s(-2) compared with the muscle 0.000 760 ± 0.000 265 0 mm s(-2), and there was a statistical difference of p = 0.002. The time-intensity curves exhibited a rapidly enhancing and a slow washout pattern on dynamic contrast-enhanced MRI.

CONCLUSIONS

Solitary fibrous tumours should be considered in cases of heterogeneous hypervascular tumours in the head and neck region. Areas of mild hyperintense intensity on T2 weighted images that are strongly enhanced after gadolinium injection are suggestive of this diagnosis. Non-restricted diffusion and rapidly enhancing and slow washout pattern time-intensity curves may be additional valuable features.

Value of MR imaging in differentiation between solitary fibrous tumor and schwannoma in the orbit

BACKGROUND AND PURPOSE

Orbital SFT is a rare tumor, often misdiagnosed as orbital schwannoma preoperatively but with different prognosis and treatment. Our aim was to evaluate MR imaging features that might distinguish orbital SFT from schwannoma.

MATERIALS AND METHODS

MR imaging including DCE scanning was performed in 9 patients with SFT and 22 patients with schwannoma in the orbit confirmed by pathology. Location, shape, margin, signal intensity, homogeneity, enhancement pattern, ER, and TIC of the tumors were retrospectively evaluated.

RESULTS

There was a statistically significant difference between SFT and schwannoma in location and T2 signal intensity (P < .05). A statistically significant difference was also found regarding the enhancement pattern of the very high-signal-intensity areas shown on T2-weighted imaging and the type of TICs (P < .01).

CONCLUSIONS

MR imaging is useful in differentiating orbital SFT and schwannoma. The enhancement pattern of the very high-signal-intensity areas shown on T2-weighted imaging and the type of TICs on DCE MR imaging played an important role in differentiating orbital SFT from schwannoma.

F-18 FDG PET/CT and Tc-99m sulfur colloid SPECT imaging in the diagnosis and treatment of a case of dual solitary fibrous tumors of the retroperitoneum and pancreas

Although FDG PET is increasingly used for the staging of many types of sarcoma, little has been written regarding the FDG PET imaging characteristics of solitary fibrous tumor. We report a patient undergoing FDG PET/CT surveillance for squamous cell carcinoma of the tongue who was incidentally found to have two soft tissue masses in the retroperitoneum and pancreatic tail. Due to their low degree of FDG avidity, they were followed conservatively for approximately one year as they gradually increased in size. Technetium-99m sulfur colloid SPECT helped confirm that the pancreatic tail mass was not a splenule, after which both lesions were surgically resected and found to be extrathoracic solitary fibrous tumors without malignant features. These findings suggest that, as with other low-grade sarcomas, benign extrathoracic solitary fibrous tumors exhibit relatively little glycolytic metabolism in vivo.

Somatic and visceral solitary fibrous tumors in the abdomen and pelvis: cross-sectional imaging spectrum

Solitary fibrous tumors (SFTs) are a unique group of mesenchymal neoplasms of fibroblastic or myofibroblastic origin. These tumors were originally described as "benign fibrous mesotheliomas" of the pleural cavity and were erroneously thought to be confined to the serosal surfaces (due to a putative mesothelial or submesothelial origin). It is now established that SFTs are ubiquitous neoplasms with both pleural and extrapleural distribution. Extrapleural SFTs commonly occur in middle-aged adults and manifest as asymptomatic, slow-growing, large tumors. Fewer than 5% of patients with SFTs present with symptomatic hypoglycemia. SFTs are histopathologically diverse with a variable admixture of fibroblasts or myofibroblasts, numerous thin-walled vessels, and dense fibrosis. Tumors previously categorized as hemangiopericytomas are now considered cellular variants of SFTs. At imaging, SFTs demonstrate remarkable heterogeneity, with variable degrees of enhancement, necrosis, or hemorrhage. Although most extrapleural SFTs have a benign clinical course, 10%-15% of these tumors demonstrate aggressive behavior in the form of recurrence or malignancy.

Solitary fibrous tumor originating in the pelvis: a case report

A 52 year old male presented with changes in bowel movements, and a mass was detected on digital rectal exam. Both CT and MRI revealed a large pelvic and gluteal mass filling the pelvic cavity displacing the adjacent pelvic structures. After surgical removal, pathology revealed solitary fibrous tumor; a rare neoplasm uncommonly discovered in the thorax, and even less commonly in extrapleural locations. We discuss in this article imaging findings and histological features of extrapleural solitary fibrous tumor.