Malignant Solitary Fibrous Tumor of the Orbit

PURPOSE: Solitary fibrous tumor (SFT) is a rare tumor of the pleura, mediastinum, pericardium and other organs affecting predominantly middle-aged patients. SFT arising in the orbit is extremely rare, and its malignant form is even rarer. The authors herein describe a case of malignant solitary fibrous tumor of the orbit. CASE SUMMARY: A 67-year-old male presented with a 4-month history of right proptosis. On ophthalmologic examination, 9-mm proptosis was observed in the right eye, and extraocular movements were limited in all directions of gaze. CT scan and MR imaging showed a lobulated, well-enhancing mass adjacent to the lateral rectus muscle in the superolateral retrobulbar space. Excisional biopsy through a lateral orbitotomy was performed. Histopathological examination showed proliferation of spindle cells with a fascicular pattern interspersed with bands of collagen, increased cellularity, cellular pleomorphism, hemorrhage, necrosis and high mitotic activity. Immunohistochemical staining revealed diffuse positivity for CD34, CD99, Ki67 and p53, and malignant SFT was diagnosed. CONCLUSIONS: Malignant SFT should be considered in the differential diagnosis of acutely progressing unilateral proptosis.

Malignant Solitary Fibrous Tumor of Retroperitoneum Mimicking Gastric Submucosal Tumor / 대한소화기학회지

Solitary fibrous tumors (SFTs) are an uncommon neoplasm characterized by the proliferation of spindle cells. The diagnostic criteria of malignant solitary fibrous tumors (MSFTs) include high cellularity, high mitotic activity (4>10 HPF), pleomorphism, hemorrhage and necrosis. This tumor frequently involves the pleura and MSFTs of retroperitoneum mimicking gastric submucosal tumor are very rare. We report a rare case of MSFT that presented as a gastric submucosal tumor. A gastroscopic examination showed a large bulging mucosa in the gastric body. Abdominal computed tomography revealed a well-defined heterogeneous enhancing mass between the left hepatic lobe and gastric body. Surgical resection was performed and histologic features were consistent with a MSFT.

Solitary Fibrous Tumor That Developed in the Thigh

A solitary fibrous tumor (STF) is a relatively unusual neoplasm first described as a distinctive tumor arising from pleura. Some reports have shown that STF also affect extrathoracic regions. A 70-year-old woman was referred to our hospital for surgical treatment of an incidentally discovered thigh mass. We performed complete removal of the tumor. It was a soft tissue tumor with muscle indentation but without invasion to the surrounding muscles. The resected specimen was 7.0x6.3x5.2 cm. Histologically, the tumor was composed of a haphazard proliferation of spindle cells and epitheloid cells with hypercellularity and high mitotic activity. Immunohistochemistry showed positive immunoreactivity for CD34, CD99, bcl-2 protein, CD117, vimentin, smooth muscle actin and epithelial membrane antigen. We report, herein, on a rare case of malignant SFT in the thigh region along with a review of the literature.

Malignant Solitary Fibrous Tumor in the Perianal Region

Solitary fibrous tumors (SFT) are rare spindle-cell neoplasms that are found principally in the pleura, and extrathoracic SFTs are even less common. We report here on a case of malignant solitary fibrous tumor in the perianal region. A 47-year-old man was referred to our hospital for surgical treatment of an incidentally discovered perianal mass. Pelvic MRI showed a slightly lobulated solid mass with central necrosis in the ischiorectal fossa. We performed complete removal of tumor with using a postanal approach. The resected specimen was 6.5x5.0x5.0 cm in size, and it was an elastic solid tumor with invasion to the surrounding muscle structures. Histologically, the tumor was composed of a patternless proliferation of spindle cells with a collagenous matrix and the tumor cells showed increased cellularity, cellular pleomorphism and frequent mitotic figure. Immunohistochemical staining was positive for CD34 and negative for desmin, which indicated malignant SFT. We report here on a rare case of malignant SFT in the perianal region along with a review of the literature.

Malignant Solitary Fibrous Tumor of the Pleura in Mediastinum

Solitary fibrous tumors (SFTs) most often involve the pleura and also may encompass the peritoneum and nonserosal sites. They occur as solitary encapsulated tumors and pursue a relatively benign clinical course. The usual criteria for malignancy are high cellularity, mitotic activity (more than 4 per 10 high-power fields), cellular pleomorphism, hemorrhage and necrosis as well as infiltrative growth. We report a case of malignant SFT of pleura who presented with an anterior mediastinal mass. Grossly, it was a 10x8x6.5 cm sized, encapsulated and well-demarcated, solid neoplasm with areas of extensive necrosis. Microscopically, parallel or haphazard arrangement of spindle cells with variable degrees of collagenous background were noted. Storiform fascicle formation, hemangiopericytoma-like pattern, and epithelioid cell clusters were often intermingled. Nodular areas with high cellularity and mitotic activity (> or =10/10 HPFs) were scattered throughout the neoplasm, however no definite cellular pleomorphism was encountered. Tumor cells were immunoreactive for vimentin and CD-34, which distinguished them from the mesothelial cells. Electron microscopically, they revealed fibroblastic and myofibroblastic differentiation.