Solitary fibrous tumor of the pancreas: Case report and review of the literature

Solitary fibrous tumor (SFT) is a mesenchymal tumor typically located in the pleura, but can also be found as an asymptomatic mass in other areas, including the liver, peritoneum, kidney and salivary glands. However, SFT rarely locates in the pancreas. We present such a case of pancreatic SFT, along with a review of all reported cases. A 55-year-old man was treated surgically for an asymptomatic pancreatic mass after a rigorous preoperative control. Histologic examination of the resected specimen showed characteristics of an SFT. As only 15 cases of pancreatic SFT have been reported so far, an attempt to compare the cases was considered intriguing. We found that patients with pancreatic SFT were mainly women (81.25%), with a median age of 54 years at the time of diagnosis and a median tumor size of 5.83 cm. Pancreatic SFTs were revealed incidentally in 50% of cases, and all of them showed an enhancement through arterial computed tomography. All tumors were positive for CD34, ten were positive for Bcl-2, and twelve were negative for S100. The diagnosis of this pancreatic tumor is established by a combination of clinical suspicion, imaging procedures and histological findings, and is confirmed by immunohistochemical staining. Although the behavior of SFTs is rather benign, close clinical follow-up is recommended due to a potentially malignant nature.     

Solitary fibrous tumor of renal pelvis

A 70-year-old Japanese man was referred because of a right renal mass of 2 years in duration. Imaging studies, including magnetic resonance imaging, revealed an ovoid mass, with relatively abundant vascularity, in the right renal pelvis. Right radical nephrectomy was done and a tumor measuring 6.0 x 4.5 x 4.0 cm was found in the renal pelvis. Solitary fibrous tumor (SFT) was highly suspected by histology. Immunohistochemical study using a monoclonal antibody directed against the human hematopoietic progenitor cell antigen (CD34) stain confirmed SFT. This is the first case of SFT of the renal pelvis. Although SFT is extremely rare in urogenital organs, this tumor must be included in the differential diagnosis when we encounter urogenital tumors consisting of mesenchymal elements.     

Solitary Fibrous Tumor of the Greater Omentum,Mimicking Gastrointestinal Stromal Tumor of the Small Intestine: A Case Report

Solitary fibrous tumor (SFT) is one of the mesenchymal tumors, which rarely arises in the abdominal space. We report a very rare case of abdominal SFT, mimicking another mesenchymal tumor. A 52-year-old Japanese man was referred to our hospital for further evaluation and treatment of gallbladder polyp. Contrast-enhanced computed tomography (CT) showed an enhanced nodule within the gallbladder, and incidentally, also showed a well-circumscribed mass adjacent to the small intestine. The mass was depicted as slightly high density in plain CT, and with contrast-enhancement, the mass was partially stained in early phase and the stained area spread heterogeneously in delayed phase. Magnetic resonance imaging showed that the abdominal mass was depicted as slightly high intensity on T2-weighted imaging and low intensity on T1-weighted imaging. With double-balloon endoscopy and capsule endoscopy, we did not find any tumor inside the small intestine. These visual findings lead us to diagnose it as gastrointestinal stromal tumor of the small intestine with extraluminal growth. We planned to resect both the gallbladder polyp and the intraperitoneal tumor at the same time for pathologic diagnosis and treatment. When the operation was performed, we found a milk-white lobulated tumor on the greater omentum and the tumor was entirely resected. Microscopically, the gallbladder polyp was diagnosed as tubular adenoma, and the omental tumor was diagnosed as SFT. It is important to bear in mind that omental SFTs sometimes mimic other mesenchymal tumors and should be included in the differential diagnosis of abdominal tumor not revealed by endoscopy.Key words: Mesothelial tumor, Extrathoracic locationSolitary fibrous tumor (SFT) is one of the mesenchymal tumors, which was initially thought to usually arise in the pleura. In recent days, however, there have been several previously reported cases of extrapleural SFT; for example, orbit, thyroid, breast, and so on.¹ Nevertheless, SFTs arising in the abdominal space are still rare; in particular, there have been few reports of omental SFT in the past literature. We herein report a case of SFT of the greater omentum, which mimicked another mesenchymal tumor.     

Nesidioblastosis with hyperinsulinemic hypoglycemia in adults: Report of two cases

We report herein the cases of two women, aged 34 years and 39 years, respectively, found to have hyperin-sulinemic hypoglycemia after presenting with a history of episodes of temporary loss of consciousness, nausea, and fainting. Under the suspected diagnosis of insulinoma, localization procedures were carried out, but no tumor was found. In both patients, a definite gradient in insulin concentration was found in the pancreas by percutaneous transhepatic or intraoperative portal venous sampling, and a misdiagnosis of insulinoma of the pancreatic body was made. During exploratory laparotomy no tumor was palpable in the pancreas, and intraoperative ultrasonography showed no low echoic mass in the pancreas. A distal pancreatectomy was performed in both patients, and histopathological examination of the resected specimens revealed graded slight hyperplasia of the islet cells.     

Case of retroperitoneal solitary fibrous tumor

Solitary fibrous tumor (SFT) of the retroperitoneal space is rare. We report a case of retroperitoneal tumor, diagnosed as SFT. A 69-year-old woman presented with right lower abdominal swelling, and was referred to our hospital with suspicion of right renal tumor. Abdominal ultrasound and computerized tomography (CT) showed a mass (about 15 x 14 x 10 cm) in the right abdomen. The tumor was thought to be right renal rumor, and right radical nephrectomy was performed. In the excised specimen the tumor was not connected to gastrointestinal tract, peritoneum, or right kidney. The histological and immunohistochemical examination of the specimen revealed SFT. The tumor has malignant potential with partially increased mitotic activity and cellularity in the histological examination. The patient is healthy and without evidence of recurrence or metastasis 26 months from surgery.     

Pleural solitary fibrous tumor from diaphragm, being suspected of liver invasion; report of a case

We report a case of solitary fibrous tumor (SFT) from diaphragmatic pleura. A 71-year-old female was admitted to our hospital because of an abnormal shadow on chest X-ray. A preoperative imaging study revealed a mass on her right diaphragm. At thoracoscopic exploration, the tumor was found to originate from diaphragm and was suspected of liver invasion. The conversion to open thoracotomy was introduced to perform appropriate surgical procedure. Pathological examination revealed proliferation of spindle cells and collagen fibers. Immuno-histochemical findings showed positive immunostaining for cell differentiation (CD) 34 and vimentin. The tumor was diagnosed as SFT with malignant potential.     

Solitary fibrous tumor of the adrenal gland with renal cell carcinoma and angiomyolipoma at the same time; a case report

Solitary fibrous tumor (SFT) is a neoplasm of pleura and its occurrence in the retroperitoneal space is rare. We report a case of SFT of the adrenal gland associated with ipsilateral renal cell carcinoma (RCC) and angiomyolipoma (AML). A 48-year-old woman was referred to our hospital for a left renal AML. Computed tomography (CT) in our hospital showed a left adrenal mass (25 x 20 mm). Because the adrenal tumor was nonfunctioning, she was followed at outpatient clinic. Four years later, CT showed an increase in the left adrenal tumor size (42 x 30 mm) and a left RCC. Left adrenectomy and partial nephrectomy for RCC and AML were simultaneously performed. Histological examination revealed adrenal SFT and clear cell carcinoma and AML of the kidney. We present a brief review on histological characteristics of retroperitoneal SFT and its occurrence in the adrenal grand region.     

Solitary fibrous tumor of the pelvis: an uncommon soft-tissue tumor. A case report

A rare case of Solitary fibrous tumor (SFT) of the pelvis is reported. A 76-years-old man presented with a low abdominal pain, acute urine retention and constipation. Imaging studies (US, CT MR) showed an 17 x 10 x 9 ovoid mass in the pelvis, dislocating bladder and rectum. Finally, trans-rectal needle biopsy suggested the diagnosis of SFT. En bloc excision of tumor and rectum (because of strong adhesions) was performed. Histological examination showed spindle and fibroblastic-like cells dispersed in collagenous areas with positive stains for CD34, bcl-2, CD99 and it confirmed diagnosis of SFT. No postoperative complications occurred, only vesico-sphincter dyssynergia was found by urodynamics. After 5 years, patient is disease-free. SFT is, usually, benign tumor with slow growth and excellent prognosis. Complete surgical resection is the only curative treatment. However, 10-15% of SFT are malignant and histological findings cannot always predict clinical behaviour. For this reason, careful and long term follow-up is necessary after surgery.     

Solitary fibrous tumor of the thoracic spinal cord

A 63-year-old woman presented with a rare case of primary solitary fibrous tumor (SFT) occurring in the extramedullary thoracic spinal cord. T1-weighted magnetic resonance (MR) imaging showed the tumor as a mildly hypointense area with homogeneous enhancement by gadolinium. T2-weighted MR imaging showed a hypointense mass with peritumoral edema. The tumor arose from one of the posterior spinal roots, with no attachment to the dura. The tumor was clearly circumscribed from the surrounding cord tissue and easily removed. Histological examination showed the tumor predominantly consisted of spindle cells separated by abundant collagen matrix fibers. Tumor cells were strongly positive for vimentin and CD34, but negative for glial fibrillary acidic protein, S-100 protein, epithelial membrane antigen, myelin basic protein, and keratin. SFT should be considered in the differential diagnosis of spindle cell central nervous system neoplasms, although SFT is extremely rare in the spinal cord.     

Spleen-preserving laparoscopic distal pancreatectomy after division of the splenic vessels

A 37-year-old woman with a history of syncope was hospitalized with a diagnosis of hypoglycemia due to insulinoma. Computed tomography (CT) and magnetic resonance imaging revealed an enhanced solid mass, 1.5 cm in diameter, at the tail of the pancreas. Angiography via the splenic artery revealed a hypervascular mass. Because the tumor was located deep in the pancreatic parenchyma, laparoscopic distal pancreatectomy was performed. The pancreas was exposed by dissecting the greater omentum, and the tumor was located by intraoperative ultrasonography. After division of the splenic artery, the pancreas, main pancreatic duct, and splenic vein were transected with an endoscopic linear stapler. The pancreatic pedicle was divided at the splenic hilum to preserve the spleen. The postoperative course was uneventful except for the appearance of splenic infarction on a CT scan 2 weeks after surgery but without any overt symptoms. Spleen-preserving laparoscopic distal pancreatectomy by division of splenic vessels is a feasible treatment option for benign pancreatic disease.     

Solitary fibrous tumor of the liver

We report a new case of benign solitary fibrous tumor (SFT) of the liver. A 65-year-old man presented to our unit with upper right abdominal discomfort. On examination abdominal distension was present and palpation showed a large firm mass in the right hypochondrium and epigastrium. The patient’s past medical history was not significant and laboratory tests were normal. Ultrasonography and computed tomography showed a large tumor, 20 cm in diameter, in the right lobe of the liver. An extended right hepatectomy was performed. The tumor measured 30 × 28 × 14 cm and weighed 4725 g. Microscopic evaluation showed a benign SFT of the liver with tumor cells typically positive for vimentin and CD34. The postoperative course was uneventful, and the patient is alive 30 months after surgery. This is a rare neoplasm of mesenchymal origin that occasionally involves the liver in adult patients. Most SFTs are benign, but some may have malignant histological features and recur locally or metastasize. Because of their rarity, overall experience has not been significant and little has been published concerning this tumor, Including the present one, 28 cases have been reported in the English literature. Surgery is the mainstay of treatment. Little can be said about the benefits of adjuvant radiochemotherapy in these patients. As SFT of the liver is often a benign neoplasm, chemotherapy or radiotherapy should not be necessary, and should be reserved for when resection is incomplete and/or histological examination reveals features of malignancy. Surgeons must be aware of SFT of the liver, and this neoplasm should be included in the differential diagnosis of a single large hepatic mass.     

A resected case of solitary fibrous tumor of the pleura

A 45-year-old female with solitary fibrous tumor (SFT) of the pleura was reported. Chest X-ray and CT scan on admission showed a large tumor in the right thoracic cavity. A preoperative needle biopsy was performed. The microscopic appearance of biopsied specimen revealed many spindle cells. And an immunohistochemical study was positive for CD 34 and negative for keratin, epithelial membrane antigen, alpha-smooth muscle actin, S-100 protein. So SFT was strongly suspected and an operation was performed. A tumor arised from the visceral pleura of right middle lobe and was pedunculated. The tumor was 13 x 10 x 7.5 cm in size. An immunohistochemical study of the tumor was positive for CD 34, and negative for SMA, ki-67. From these immunohistochemical stainings and microscopic findings, the tumor was diagnosed as SFT. An immunohistochemical study of the tumor seems to be very useful for the diagnosis of SFT.     

Solitary fibrous tumor of the orbit. Case report and review of the literature.

BACKGROUND: Solitary fibrous tumor (SFT), which usually presents in the pleura and is thought to be mesothelial in nature, has been recently discovered in extrapleural sites, including the orbit. Presently ultrastructural studies show absence of epithelial-mesothelial features, and reactivity of the tumor cells to CD34 antigen on immunohistochemical analysis suggests the mesenchymal origin of such tumors. CASE DESCRIPTION: A 40-year-old woman had a 4-year history of progressive swelling of her right upper lid and a slow-growing palpable mass of the orbit. CT and MR imaging showed a well circumscribed, nonenhanced extraconal mass with mild erosion of the right orbital roof. The tumor was totally excised. Histological examination disclosed a spindle-cell tumor in a dense fibrous tissue. Immunohistochemistry showed positive staining for vimentin and CD34. We review the clinical, diagnostic, and surgical features of 22 orbital SFTs including the present case. CONCLUSIONS: Orbital SFT generally pursues a slow, indolent, and nonaggressive course, reaches a size up to 4.5 cm, and can be cured by a single excision. It must be immunohistochemically differentiated from other spindle-cell tumors of the orbit.     

An Aggressive Solitary Fibrous Tumor with Evidence of Malignancy: A Rare Case Report

Solitary fibrous tumor (SFT) is rare mesenchymal neoplasm that has been originally and most often documented in the pleura. Recently, the ubiquitous nature of the SFT has been recognized with reports of involvement of numerous sites all over the body, i.e, upper respiratory tract, breast, somatic tissue, mediastinum, head, and neck, etc. The diagnosis of SFT still remains an enigma in our field. Furthermore, malignant SFT is extremely rare and only two cases have been reported in the oral cavity till date. Here, we present a rare case report of an aggressive solitary fibrous tumor which presented as a palatal mass and extended throughout the middle cranial fossa and exhibited features of malignancy.     

A case of solitary fibrous tumor in the cerebral convexity indicating its non-dural origin

We report a case of solitary fibrous tumor (SFT) in the cerebral convexity, and present characteristic radiological and surgical findings to determine its origin. The patient was a 59-year-old man with mental dullness and mild gait disturbance. CT scan and MR images showed a highly enhanced large mass lesion mimicking a meningioma in the left parietal convexity. However, neither dural enhancement nor tail sign indicative of meningioma was observed. Angiography showed prominent feedings from branches of the internal carotid and basilar arteries rather than the external carotid artery. For this reason, presurgically, we suggested hemangiopericytoma or other specific meningiomas as a differential diagnoses. Surgery confirmed that the tumor had no attachment to the dura mater and was covered by the arachnoid membrane. The bottom of the tumor adhered tightly to brain tissue. The origin was considered to be the brain surface, pia mater or a part of the arachnoid membrane. Histopathologically, the tumor was diagnosed as a SFT with findings of "attemless pattern" and diffuse CD34 staining. The radiological and surgical findings of the present case indicated in the cerebral convexity as a unique site of origin of SFT.     

Solitary fibrous tumor of the liver with CD 34 positivity and hypoglycemia

We report a new case of solitary fibrous tumor (SFT) of the liver, an extremely rare neoplasm. Including the present case no more than ten cases are reported in the English-language literature. To date there is no definite proof of the origin of this tumor. Both mesothelial and fibroblas-tic genesis has been postulated. The monoclonal antibody CD 34 has recently been used for the characterization of SFT. SFT would appear to be histogenetically related to a CD 34 — positive fibroblastic stem cell. A 61-year-old woman was admitted to our department with epigastric and right hypochondriac pain, weight loss, and hypoglycemia. Ultrasonography and computed tomography demonstrated a large heterogeneous mass in the right hepatic lobe. A right hepatectomy was performed. The tumor weighed 2850 g and microscopic section revealed a peculiar random pattern, the so-called patternless pattern of spindle tumor cells separated by abundant thick collagen bands. The tumor presented a number of highly cellular areas composed of plump spindle cell with hyperchromatic nuclei and rare mitotic figures. Ninety percent of the neoplastic cells displayed strong immunoreactivity for CD 34/My 10. The postoperative course was uneventful and the patient is alive and well without recurrence 6 years after surgery. Received for publication on June 16, 1997; accepted on Oct. 27, 1997     

Minute malignant islet cell tumor of the pancreas: Report of a case

We present herein the case of a 73-year-old Japanese man in whom a minute malignant islet cell tumor, 7 mm in maximal diameter, was discovered. The patient was admitted to our hospital to undergo a gastrectomy for gastric cancer, at which time preoperative ultrasonography (US) revealed a minute hypoechoic mass located in the head of the pancreas. Endoscopic retrograde pancreatography, angiography, computed tomography, and magnetic resonance imaging failed to reveal the features or location of the tumor; nowever, these details were obtained by endoscopic and intraoperative US. Although intraoperative fine-needle aspiration cytology of the tumor enabled a diagnosis of islet cell tumor to be made, it failed to provide enough material to evaluate the grade of malignancy, which was confirmed by histologic examination of the enucleated tumor, allowing the appropriate surgical procedure to be decided.     

Surgical aspects of histologically unproven space-occupying lesions of the pancreas head

A suspected, but unproved malignant tumor in the head of the pancreas is a fairly common problem for surgeon. Even intraoperatively, differentiation between chronic pancreatitis and carcinoma is difficult. We try to give guidelines about what can be done with a pancreas head mass intraoperatively without previous cytology or histology. When do we have to achieve definite diagnosis at all costs, and how can we achieve it? Results of 40 intraoperative aspiration cytologies, performed for suspected pancreatic cancer were analysed. All of them were controlled by histology in the resected specimen. Intraoperative biopsy was false negative in 12.5% and the diagnosis was uncertain in 35%. These data show that a benign result by itself never excludes the presence of malignancy. If pathology will alter our decision about resection, all efforts should be made to confirm the diagnosis. On the other hand, in a case of a mass lesion with obstructive symptoms, cytology does not alter the need for surgical decompression, and some kind of resection is a reasonable option, even in case of chronic pancreatitis. Nihilistic approach in the case of pancreatic head mass with suspected but unproved malignancy is not justified. Pancreatoduodenectomy should be performed for all tumors even without histologic confirmation if an experienced team can perform it with low postoperative morbidity and mortality.     

Solitary fibrous tumors arising in abdominal wall hernia sacs.

Solitary fibrous tumor (SFT) of the peritoneum is an unusual spindle-cell neoplasm. SFT was originally described in the pleura; however it is now diagnosed in multiple extrathoracic sites. Most believe that the tumor is of mesenchymal origin and should be classified as a variant of fibroma. SFT of the pleura and peritoneum have also been called fibrous mesothelioma, and the cell of origin is felt to be a pluripotential submesothelial mesenchymal cell. Primary tumors arising in hernia sacs are rare, and we report on two patients with hernia SFT. The first is a 67-year-old man who had a diffusely thickened distal left inguinal hernia sac. Within the sac was copious myxoid material mimicking pseudomyxoma peritonei. Herniorrhaphy and orchiectomy were performed. The second is a 44-year-old woman with a midepigastric mass attached to a ventral hernia. Wide local excision was performed. Both tumors demonstrated plump spindle cells, one with myxoid background and the other with keloidal collagen. Calretinin immunostaining was positive in both tumors, whereas CD34 was negative. This suggests tumor origin from a submesothial pluripotential cell that maintains potential for mesothelial differentiation. Surgical excision is the treatment of choice with the degree of resectability being a powerful predictor of outcome.     

Recurrent solitary fibrous tumor of the falx cerebri with intraventricular extension: case report

A 61-year-old male presented with a recurrent solitary fibrous tumor (SFT) arising from the falx cerebri with intraventricular extension manifesting as nausea and vomiting. Magnetic resonance imaging showed the heterogeneously enhanced tumor in the falx, which extended to the bilateral lateral ventricles and the third ventricle. Total tumor removal was performed via the bifrontal interhemispheric approach. Histological examination showed mostly spindle cells with rich intercellular fibers. Immunohistochemical examination showed strong staining for CD34 in the cytoplasm but no staining for epithelial membrane antigen. Reexamination of the two previous tumor specimens, previously identified as fibrous meningioma, found SFT. The differential diagnosis of SFT in the central nervous system from fibrous meningioma and hemangiopericytoma requires immunohistochemistry and electron microscopy.