Disseminated malignant solitary fibrous tumor of the pleura

Solitary fibrous tumor (SFT) of the pleura typically forms a localized pleura-based mass, and most are benign. A rare case of disseminated malignant SFT of the pleura is reported. The patient was a 71-year-old man who presented with complaints of shortness of breath to his primary care physician. A diagnosis of malignant mesothelioma was suspected, based on clinical, radiological and needle biopsy findings. He was referred to our institution for surgery. An extrapleural pneumonectomy, encompassing all pleural masses, was performed. Gross examination of the resected specimen was remarkable for numerous masses, ranging in size from 0.2 to 13.5 cm, covering the majority of the visceral pleura. Histologically, the tumor was composed of short spindle cells admixed with variable proportions of collagenous stroma. There were great intra- and intertumoral heterogeneity in tumor growth pattern, cellularity, pleomorphism and mitoses. Histologically malignant areas were present in all of the masses examined. The neoplastic cells were diffusely and intensely positive for bcl-2. Most tumor cells were also strongly stained for CD34 and CD99. Staining for cytokeratin was negative. The tumor also revealed p53 over-expression. Thus, the histological and immunohistochemical features of the tumor were consistent with a disseminated malignant SFT. This report shows that SFT rarely presents with disseminated pleural involvement, and a panel with CD34, bcl-2 and cytokeratin are valuable for differentiating SFT from malignant mesothelioma and other malignant spindle cell neoplasms of the pleura.     

Solitary fibrous tumor of the kidney originating from the renal capsule and fed by the renal capsular artery

Solitary fibrous tumors (SFT) are relatively rare spindle cell neoplasms that typically arise in the pleura. Recently, extrathoracic SFT that have arisen in various anatomic sites have been recognized. The histogenesis and prognosis of SFT of the kidney are not well understood because only 11 cases have been reported. We report a case of SFT of the left kidney arising from the renal capsule. The tumor was merged with the upper pole of the left renal capsule. The angiography revealed that the renal capsule artery fed the tumor. The tumor was a well-circumscribed, solid mass attached to the renal capsule without necrosis or hemorrhage. Microscopically the bland spindle cells proliferated and were accompanied by hyalinized collagenous tissue showing patternless or hemangiopericytomatous patterns. Some glomeluri and renal tubules were entrapped by the tumor cells. There were no mitotic figures. Immunohistochemically the tumor cells were diffusely positive for CD34, CD99 and bcl-2. There was no evidence of recurrence after a 4 year follow-up visit. The origin of SFT of the kidney remains uncertain. The tumor in this case merged with the renal capsule and was fed by the renal capsular artery, which suggests that some SFT of the kidney originate from the renal capsule.     

Comparison of sporadic sclerotic fibroma and solitary fibrous tumor in the oral cavity

Sporadic sclerotic fibroma (SF) and solitary fibrous tumor (SFT) arising in the oral cavity are very rare. In this report, we describe two cases of oral pathology, one involving SF and the other involving SFT. Both cases presented with well- circumscribed, firm nodules with similar gross findings. However, the histologic findings of the SF and SFT showed rather distinct features. The SF was composed of hyalinized sclerotic collagen bundles arranged in a whorled pattern, whereas the SFT was formed by spindles cells arranged in hypo- and hypercellular areas. The immunohistochemical findings were similar in both cases; there was positivity for vimentin, CD34, and CD99, but bcl-2 positivity was only seen in the SFT. Although their histopathologies are similar, SF and SFT should be considered in the differential diagnosis of soft tissue tumors in the oral cavity.     

Solitary fibrous tumor of the kidney. Case report

Solitary fibrous tumors are rare spindle cell neoplasms usually arising in the pleura. They have, however, also been reported at extrapleural locations. Solitary fibrous tumor (SFT) of the kidney is rare. Despite its rarity, histological diagnosis of solitary fibrous tumor is crucial to avoid misdiagnosis with other more aggressive tumors arising in the kidney. We report a solitary fibrous tumor of the left kidney that presented as a malignant tumor in a 51-year-old woman, and include clinical and radiographic findings. The tumor was well circumscribed and composed of spindle cells in a collagenous stroma. Immunohistochemistry showed reactivity for vimentin, CD 34, BCL-2 protein and CD99. Immunohistochemical stains for cytokeratin, S-100, desmin, alpha-smooth muscle actin and HMB-45 were negative. A diagnosis of SFT was made based on light microscopy and immunohistochemistry.     

Advanced malignant solitary fibrous tumor in pelvis responding to radiation therapy

Solitary fibrous tumor (SFT) is a rare spindle cell neoplasm that is benign in most cases. Although SFT was first recognized to arise only in the pleura, recent reports indicate that SFT can involve a wide range of anatomical sites. To date, 17 cases of pelvic SFT have been reported. Herein is reported a case of a 74-year-old woman with a giant malignant SFT in the pelvis. Along with massive invasion to adjacent organs and multiple lung metastases detected on radiography, biopsy from the tumor through the vaginal wall showed malignant looking spindle-cell neoplasm with increased cellularity, areas of necrosis, and high mitotic activity (5/10 high-power fields). Immunohistochemically, the tumor cells were diffusely and strongly positive for CD34, CD99, and bcl-2. Based on pathological features and clinical presentation, diagnosis of malignant SFT was made. The patient received systemic and the intra-arterial chemotherapy followed by whole pelvic radiation therapy (50 Gy). Initial chemotherapies failed to control the tumor. Afterwards, improvement was observed radiologically and pathologically in the 12 months' follow up after the radiation therapy. This is the first report related to therapeutic remarks on advanced malignant SFT.     

Malignant solitary fibrous tumor of the thyroid gland: report of a case and review of the literature

Solitary fibrous tumors of the thyroid gland (T-SFT) are rarely described, with only 21 cases being reported in the English literatures, all showing benign clinical characteristics. We herein present a 76-year-old woman presenting with a 3-month history of rapidly enlarging neck masses and the CT showed masses with partial calcification in the right thyroid lobe. We performed right hemithyroidectomy and isthmectomy with negative margin under general anesthesia. Histologically, the masses consisted of pleomorphic spindle cells with high mitoses and collagen bands. Immunohistochemically, the tumor cells showed positive reactions for CD34, vimentin and bcl-2, then a diagnosis of malignant solitary fibrous tumor of the right thyroid was made. Six months postoperatively, the CT showed the recurrence of the thyroid tumor and the presence of many nodules of varying sizes throughout bilateral pulmonary lobes. To our knowledge, this is the first case of malignant solitary fibrous tumor of the thyroid gland (T-SFT) with local recurrence and pulmonary metastasis and T-SFT must be considered in the differential diagnosis of spindle cells lesions in the thyroid gland. Correct diagnosis of the malignant T-SFT plays an important role in choosing appropriate therapeutic strategies and long-term follow-up is also extremely essential for these patients.     

Solitary fibrous tumour of the kidney with sarcomatous overgrowth . Case report and review of the literature

Solitary fibrous tumour (SFT) rarely occurs in the kidney, with only one case exhibiting malignant behaviour. We report the case of a typical SFT of the kidney with sarcomatous overgrowth in a 34‐year‐old woman. This malignant component, grossly apparent as a nodular area arising in the context of the main tumour mass, consisted of CD34⁺ mitotically active atypical plump spindle‐ to epithelioid‐shaped cells, including pleomorphic multinucleated giant cells. A novel immunohistochemical finding was diffuse and strong S‐100 protein expression by sarcomatous cells. This should be kept in mind by pathologists to avoid confusion with other S‐100 protein‐positive malignant neoplasms.     

Myxoid solitary fibrous tumour: instructive case and literature review

Myxoid solitary fibrous tumour (SFT) is a rare soft tissue neoplasm, which was initially described by de Saint Aubain Somerhausen et al in 1999. Myxoid SFT is an SFT with myxoid change in 50% or more of the tumour. We report the case of a 50-year-old man with a myxoid SFT found in the right pelvis. Microscopically, the lesion was composed of spindle cells arranged in a haphazard and storiform pattern, individually separated by delicate band of collagen fibres, in a cellular and hypocellular myxoid background with hemangiopericytomatous vessels. Atypical features (necrosis, hypercellularity or increased mitotic figures) were absent. Immunohistochemistry demonstrated tumour cells that were highlighted by CD34, CD99, and BCL2. The lesion was resected and to date, there is no evidence of tumour recurrence or metastasis. Myxoid SFT like classical SFT may be associated with an indolent clinical course and favourable prognosis. Its recognition is crucial because of its morphological similarities to myxoid spindle cell neoplasms that have different prognoses and treatment options.     

Orbital hemangiopericytoma and solitary fibrous tumor: a morphologic continuum

Solitary fibrous tumors (SFT) and hemangiopericytomas (HPC) are soft tissue tumors with known histologic and immunohistochemical overlap. A series of these tumors located in the orbit were analyzed in order to determine whether they could be re-classified based on currently recognized histologic criteria. Ten orbital spindle cell lesions, all of which were positive for CD34 antigen, were examined. Diagnostic criteria for SFT included a cytologically bland spindle cell lesion with variable cellularity and focal dense collagenization with diffuse, strong CD34 reactivity, while the criteria for HPC required a more monotonous cellular proliferation without significant variability in cellularity, a "staghorn" vascular pattern, minimal collagenization, and focal or absent CD34 staining. Tumors with typical histologic and immunohistochemical features of HPC or SFT were diagnosed as HPC and SFT, respectively. Those tumors with histologic or antigenic profiles not classic for HPC or SFT were defined as 'indeterminate.' Three lesions were classified as SFT and 1 tumor was diagnosed as HPC through use of the above-cited histologic criteria. All lesions showed positive staining of tumor cells with CD34 antigen in varying amounts and were negative for cytokeratin AE1-3, epithelial membrane antigen, CD68, and Factor XIIIa. One solitary fibrous tumor focally stained for S-100 protein and 1 hemangiopericytoma was focally positive for HHF-35. Of the 10 analyzed tumors, 6 were classified as 'indeterminate.' Furthermore, 1 lesion whose primary histology was that of an SFT recurred 9 years later with an appearance consistent with an 'indeterminate' lesion. Our results call into question the present histologic separation of HPC and SFT in the orbit. As in other sites, including deep soft tissue, these data suggest that SFT and HPC are 2 lesions whose morphologic features are best interpreted to exist along a continuum, rather than 2 lesions with distinctly defined histopathology.     

Solitary fibrous tumor of the pancreas

A 67-year-old woman was found to have an incidental pancreatic mass on computed tomographic examination of her abdomen in the course of investigation of hematuria. The radiologic features were of a hypervascular mass in the uncinate process of the head of the pancreas, and a preoperative diagnosis of a neuroendocrine tumor was favored. A Whipple procedure was performed. The uncinate process contained a 2.6-cm well-circumscribed mass. Histologic evaluation showed a lesion composed of alternating hypercellular areas made up of spindle-shaped cells and hypocellular areas with hyalinized, keloidal-like fibrous tissue. Occasional dilated vascular channels and entrapped pancreatic tissue were present within the lesion. Immunohistochemistry showed the lesion to be CD34, CD99, and bcl-2 positive. No evidence of atypia was noted, and the overall impression was of a benign solitary fibrous tumor of the pancreas. This is an unusual primary spindle cell neoplasm of the pancreas and should be considered in the differential diagnosis of all spindle cell lesions that occur in the pancreas.     

Fat-forming solitary fibrous tumor of the kidney: a case report and literature review

Fat-forming solitary fibrous tumor (SFT) is a rare soft tissue tumor. Herein, we reported a 30-year-old woman was found to have a solid mass measuring 60×45 mm in the right kidney on an abdominal computed tomography scan. The tumor was well-circumscribed and composed of cellular nodules with the classic SFT admixed with clusters and lobules of mature adipocytes. Immunohistochemistry staining showed that the tumor cells were diffusely and strongly positive for CD34 and Bcl-2, focally and weakly positive for CD99 and EMA. Mature adipocytes were positive for S-100 protein. Ki-67 expression was found in approximately 2% of tumor cells. However, tumor cells were negative for cytokeratin, S-100 protein, HMB-45, Melan-A, SMA, and CD117. We made the pathological diagnosis of fat-forming SFT of the right kidney. The differential diagnosis includes angiomyolipoma, liposarcoma, spindle cell lipoma, sarcomatoid renal cell carcinoma, synovial sarcoma, and gastrointestinal stromal tumor. The patient was alive and well without evidence of recurrence or metastasis at 19 months after tumor resection.     

Myxoid solitary fibrous tumor: a study of seven cases with emphasis on differential diagnosis.

Focal myxoid change is a well-recognized feature of solitary fibrous tumor (SFT), but to date, predominantly myxoid examples of SFT have not been reported. We describe seven cases of SFT in which stromal myxoid change affected 50% or more of the tumor examined, thus obscuring typical diagnostic features. Patients ranged in age from 35 to 68 years old (median, 45 yr), with an equal sex distribution. Tumor locations included pleura, orbit, and periparotid subcutaneous tissue, as well as four cases in deep soft tissue (two in the abdominal wall and one each in the chest wall and thigh). Myxoid areas were identified grossly in four cases. Histologically, the lesions were composed of bland spindle cells disposed haphazardly or with a lacy or reticulated appearance in a myxoid, richly vascularized stroma These myxoid areas were punctuated by small cellular aggregates in four cases, and areas showing diagnostic features of SFT were present in five of seven primary excision specimens. Atypical features suggestive of malignancy were not present in any of the cases. Immunohistochemically, all of the seven cases stained positively for CD34 and CD99 (013), and all were negative for smooth muscle actin, desmin, S-100 protein, epithelial membrane antigen, and pan-keratin. There were no recurrences or metastases reported in four patients with limited follow-up (median duration, 19 mo). Recognition of this uncommon morphologic subset of SFT is important because of possible confusion, particularly in small biopsy specimens, with a variety of myxoid spindle cell neoplasms with different biologic potential. These include low-grade fibromyxoid sarcoma, myxoid synovial sarcoma, malignant peripheral nerve sheath tumor, low-grade myxofibrosarcoma, myxoid liposarcoma, myxoid spindle cell lipoma, myxoid neurofibroma, and so-called "hemangiopericytoma."     

Large solitary fibrous tumor of the oral cavity—Report of a case

The solitary fibrous tumor (SFT) is a rare soft tissue tumor with a substantially benign clinical behavior. The SFT of the oral cavity is a very uncommon entity. It is also of complicated diagnosis because of its extensive morphologic diversity and because of its similarity to many mesenchymal tumors. A 44-year-old man was referred for management of an asymptomatic lesion in the left buccal mucosa, which had been identified 10 years earlier. Intra-oral examination revealed a well-demarcated, fibroelastic, rounded exophytic mass located in the left buccal mucosa. The mass was covered with a non-ulcerated mucosa of normal color and measured approximately 4.0 cm in diameter. Histopathological examination showed proliferation of spindle-shaped cells arranged in fascicles and in a patternless pattern, highly vascularized, with focal staghorn vessels. Immunohistochemical analysis revealed diffuse positivity for CD34 and focal positivity for Bcl-2. Awareness of the morphological diversity of SFT coupled to a judicious use of appropriate immunohistochemical probes should prove valuable to accurately segregate SFT from other spindle cell neoplasms.     

Solitary fibrous tumor of the thyroid gland

Solitary fibrous tumor is a spindle cell neoplasm rarely arising in the thyroid gland. We present a 78-year-old man with the diagnosis of solitary fibrous tumor of the thyroid gland resected by subtotal thyroidectomy. Fine needle aspiration cytology via ultrasound guidance demonstrated a hypocellular aspirate that revealed follicular epithelial cells with mild nuclear atypia and scattered spindle cells with bland nuclei. Histologically, the patternless proliferation of spindle cells was seen among collagenous bundles, accompanied by hemangiopericytomatous vessels, and variously dilated follicles with mild atypical cells having slightly enlarged nuclei, indicating adenomatous goiter. The neoplastic spindle cells showed diffuse immunoreactivity to CD34, bcl-2, CD99 and vimentin, but were negative for cytokeratins, calcitonin, TTF-1 and CD5. Although solitary fibrous tumor arising in thyroid gland is rare, this tumor should be included in the differential diagnosis of thyroid spindle cell tumors and also that of adenomatous.     

Solitary fibrous tumor of the urinary bladder

Solitary fibrous tumor (SFT) is a distinct spindle cell tumor arising mainly in the pleura, however, SFT of extra-pleural sites had been reported. To our knowledge, five cases of the urinary bladder SFT had been reported. We have recently experienced a case of SFT of the urinary bladder in a 56-year- old man who was admitted to the hospital with a 4-month history of voiding difficulty, frequency, and residual urine sensation. A computerized tomography scan revealed a 12cm sized intravesical mass. The mass was marginally excised under the impression of it being a benign spindle cell tumor by pre-operative needle biopsy. On gross examination, the mass was multinodular, creamy white, and the cut surface was fibrotic with a rubbery consistency. Microscopic examination revealed haphazardly arranged spindle cells with a lace-like deposition of inter- and pericellular collagen. Areas of increased cellularity show nuclear atypia and occasional mitoses (2-3/10HPF). The immunohistochemical staining revealed an intense CD34 and bcl-2 immunoreactivity. Although the exact biologic behavior of these tumors has not been clarified, most of the reported cases have undergone a benign clinical course.     

A case of solitary fibrous tumor of the kidney: an immunohistochemical and ultrastructural study with a review of the literature

A solitary fibrous tumor (SFT) is an unusual spindle cell neoplasm that usually arises in the pleura but rarely occurs in the kidney. Despite its rarity, histological diagnosis of SFT is crucial to avoid misdiagnosis with other malignant tumors in the kidney. We report a SFT of the left kidney that presented as a malignant tumor on radiographic findings in a 75-year-old Japanese woman. The tumor was well circumscribed and composed of a mixture of spindle cells and dense collagenous bands with no areas of necrosis or cystic changes noted macroscopically or microscopically. Electron microscopy showed fibroblast-like cells with well-developed rough endoplasmic reticulum, surrounded with collagen fibers. Immunohistochemistry revealed reactivity for vimentin, CD34, Bcl-2, and CD99, but no staining for cytokeratin, S-100, desmin, actin, D2-40, or epithelial membrane antigen (EMA). These findings were compatible with those of SFT. Although SFT of the kidney is extremely rare, this tumor must be included in the differential diagnosis when we encounter renal tumors consisting of mesenchymal elements. Immunohistochemical study is the key to diagnosis for SFT, and ultrastructural study is useful for its diagnosis.     

树突状纤维黏液脂肪瘤的临床病理学研究

目的探讨树突状纤维黏液脂肪瘤的临床病理特征,并讨论与其他易于混淆的软组织肿瘤的鉴别诊断。方法收集8例树突状纤维黏液脂肪瘤,观察和分析其临床和病理组织学特征,并通过免疫组织化学标记链霉素卵白素生物素(LSAB)法,分析其CD34、bcl-2、波形蛋白、细胞角蛋白(CK)、上皮膜抗原(EMA)、S-100、HHF35和平滑肌肌动蛋白(SMA)等的表达。结果该肿瘤主要见于中老年男性皮下软组织或肌筋膜;主要分布在颈、背、肩及小腿,也可见于面部和足部。大体上边界清楚或有薄包膜,切面部分呈黏液样或胶冻状。该肿瘤在组织形态学上以成熟脂肪组织、增生的梭形细胞或星状细胞、黏液样及纤维化间质等为主要成分,在不同区域以不同的比例混杂构成。梭形细胞或星状细胞伸出细长分枝状胞质突起是其形态特征之一。无细胞异型性和核分裂象。此外,该肿瘤常有较丰富的丛状小血管和毛细血管,间质有肥大细胞、小淋巴细胞及浆细胞浸润。免疫组织化学染色梭形细胞显示CD34、bcl-2和波形蛋白强阳性,而HHF35、SMA和S-100阴性,肿瘤中所有成分对CK和EMA呈阴性反应。结论树突状纤维黏液脂肪瘤在临床表现、病理组织学改变以及免疫组织化学反应等方面有其独自的特点。该肿瘤似乎是介于梭形细胞脂肪瘤和软组织孤立性纤维性肿瘤的中间类型。需注意与黏液性脂肪肉瘤和黏液性恶性纤维组织细胞瘤鉴别诊断。该肿瘤生物学行为为良性,只需局部手术切除。     

Solitary fibrous tumor of the pancreas: a case report

Solitary fibrous tumor (SFT) is an unusual mesenchymal neoplasm that most often arises in the pleura; however, it has recently been described in a number of extrapleural sites. This report describes an extremely rare case of a benign SFT arising in the pancreas. A 41-year-old woman presented in the clinic with right upper abdominal pain. Subsequent ultrasonographic studies revealed a 1.5x1.5x1.4 cm hypoechoic mass within the pancreatic body, which was later confirmed on both helical computerized tomography and magnetic resonance imaging studies. An endocrine tumor was clinically suspected. Laparoscopic enucleation of the mass was performed. Microscopically, the tumor was composed of bland uniform spindle cells arranged between collagen bundles. On immunohistochemical studies, these spindle cells were positive for CD34 and bcl-2 but negative for cytokeratin (AE1+AE3 and Cam5.2), smooth muscle actin, desmin, S-100, and c-kit. Based on the light microscopic morphology and immunohistochemical staining profile, the diagnosis of SFT was rendered.     

Solitary fibrous tumor of the vagina

The solitary fibrous tumor (SFT) is a rare tumor that most commonly arises in the pleura. Recent evidence has indicated that this tumor originates from mesenchymal, probably fibroblastic, cells and is not restricted to the pleura. However, its occurrence in the female genital tract is extremely rare. We report a case of primary SFT that originated from the vagina in a 34-year-old female. It was a pedunculated polypoid tumor and occurred at the site of scar tissue, caused by laceration during her last labor 7 years previously. Histologically, the tumor was predominantly composed of a random proliferation of spindle cells, intimately admixed with collagen. Immunohistochemically, the cells were strongly positive for CD34, vimentin and bcl-2, but were negative for S-100 protein, neuron-specific enolase, smooth muscle actin, desmin, CD68, cytokeratins and epithelial membrane antigen. To the best of our knowledge, this is the first reported case of a primary vaginal SFT in the English literature. Our report suggests to include SFT in the differential diagnosis of a spindle cell neoplasm originating from the vagina.