Solitary fibrous tumors of soft tissue. A clinicopathologic and immunohistochemical study of 12 cases

Solitary fibrous tumours of the lower gingiva: a case report

Solitary fibrous tumours (SFTs) are rare lesions in the oral cavity. Typically they arise in the pleura. We report a lesion occurring in the lower anterior gingiva. In histochemical examination, the spindle-shaped, neoplastic cells stained strongly for CD34 antigen and vimentin, but did not stain for desmin, smooth-muscle actin, muscle actin and S-100 protein. The expression of CD34 antigen and vimentin were useful for the differential diagnosis.

Intrarenal solitary fibrous tumor of the kidney report of a case with emphasis on the differential diagnosis in the wide spectrum of monomorphous spindle cell tumors of the kidney

Solitary fibrous tumor (SFT) is a neoplasm that can occur in the urogenital tract, and is also reported occurring in the spermatic cord, seminal vesicles, urinary bladder, prostate, and kidney. Furthermore, it is most important to consider its existence in the kidney, because it is usually diagnosed as renal cell carcinoma pre-operatively. To our knowledge, only 10 cases of SFT have been reported in the kidney to date. We report the clinico-pathological features of an intrarenal SFT occurring in a 31-year-old woman. The tumor, measuring 8.6 cm in its greatest diameter, completely replaced the cortex and the medulla of the middle region of the right kidney, compressing the pelvis. Radiological imaging was consistent with a renal cell carcinoma. Histologically, the tumor was composed of a proliferation of bland-looking vimentin+, CD34+, bcl2+ and CD99+ spindle cells exhibiting a haphazard to storiform growth pattern, pushing borders, and a low mitotic rate (2 mitoses x 10 HPF). We placed emphasis on the differential diagnostic problems, i.e., its differentiation from other primary monomorphous benign and malignant spindle cell tumors of the kidney, such as fibroma, benign fibrous histiocytoma, hemangiopericytoma, inflammatory myofibroblastic (pseudo-)tumor, leiomyoma, angiomyolipoma with predominant spindle cell smooth muscle component, benign peripheral nerve sheath tumors, renal mixed epithelial/stromal tumors, adult type mesoblastic nephroma, fibrous type monophasic synovial sarcoma, malignant peripheral nerve sheath tumors, fibrosarcoma, and low-grade fibromyxoid sarcoma.

Solitary fibrous tumor of the parotid gland: a case report

The solitary fibrous tumor is traditionally associated with a mesothelial-lined surface. However, any organ with mesenchymal tissue has the potential for developing this tumor; therefore, it has been described in organs not associated with serosal surfaces. We report a case of solitary fibrous tumor of the parotid gland. Microscopically, the tumor showed a patternless arrangement of spindle cells in a fibrotic background and prominent vascular structures of varying size. Tumor cells showed a strong immunoreactivity for CD34 and bcl-2 antigens, but the tissue was negative for antibodies directed against actins, S-100 protein, and cytokeratins. One year after excision, the patient was alive and without evidence of disease.

Solitary fibrous tumors of the pleura

Solitary fibrous tumor of the pleura is a mesenchymal tumor that has been increasingly recognized over the past few years. The tumor was initially described in the pleura, but it has been reported in many other sites lately. Although the majority of these tumors have a benign course, the malignant form still remains enigmatic. Indeed, the behavior of these tumors is often unpredictable and does not always correlate with histologic findings. In addition, benign tumors may remain unproblematic for several years before changing into a malignant form. In order to define more precisely the clinical behavior of solitary fibrous tumors of the pleura, we reviewed the literature with particular attention to the clinical presentation, histopathologic characteristics, and cytogenetic differentiation of these tumors. A staging system and an algorithm for the management and follow-up of these patients are proposed.

Tumor fibroso solitário da meninge: relato de caso

O tumor fibroso solitário (TFS) é neoplasia mesenquimal rara, originalmente descrita na pleura e sendo mais recentemente também observada em vários outros sítios. Sua extensão para estruturas adjacentes não é incomum. O acometimento da meninge pelo TFS é raro, havendo relato de apenas vinte e seis casos na literatura. Apresentamos o caso de uma paciente de 25 anos, sexo feminino, com crises convulsivas tônico-clônicas generalizadas desde há seis anos. Durante a investigação, foi diagnosticado tumor em região occipital esquerda. A paciente foi submetida à craniotomia occipital, com exérese completa do tumor. O diagnóstico histopatológico e imuno-histoquímico foi de tumor fibroso solitário da meninge. Após seguimento pós-operatório por três anos, a paciente mantém o exame neurológico sem alterações e não apresenta evidência de recidiva nos controles tomográficos. É apresentada também uma breve revisão da literatura.

Chromosomal imbalances in meningeal solitary fibrous tumors

We present the results of a comparative genomic hybridization (CGH) analysis of three meningeal solitary fibrous tumors (SFT). One case showed loss of chromosome 3 and two tumors had deletions of the region 3p21-p26. Other chromosomal losses included 4p15, 8q22-q24, 10, 11q14-q25, 17q11- q23, 20, and 21 in one case each. In addition, there were gains of 18p11-p13 in one case, and 1p11-p36 and 20q11-q13 in another. To our knowledge, there are no previous CGH or cytogenetic data on meningeal SFT, and loss of material on chromosome 3 has not been described in SFT at other sites. Our findings are discussed in relation to published molecular genetic and cytogenetic data on meningioma and hemangiopericytoma, the two lesions with which meningeal SFT are most likely to be confused.

Solitary fibrous tumour in the deep soft tissue of the neck in a Chinese man

Originally described in the pleura, solitary fibrous tumour (SFT) is now reported in a variety of extrapleural sites. However, description of SFT in the deep soft tissue of the neck is very rare. In this report, we document the neoplasm, deep to the right platsyma muscle but superficial to the deep fascia just above the clavicle, in an otherwise well 50-year-old Chinese man. Histological examination of the excised specimen disclosed spindle-shaped cells disposed in short fascicles as well as randomly in association with areas of varying cellularity, keloidal hyalinisation of the stroma and haemangiopericytoma-like vessels. The tumour cells were CD34-, bcl-2- and CD99-positive. Since histological features may not accurately predict the biological behaviour of this tumour, careful long-term follow-up is advocated.

Solitary fibrous tumour of the mouth: report of two cases involving the tongue and cheek

We describe two additional cases of solitary fibrous tumour (SFT) affecting the mouth. SFT is very uncommon in the oral cavity and we found only 14 cases reported in the literature. Our two cases were well circumscribed, slow growing tumours that, after surgical removal, did not recur. Case 1 was a 3 cm nodule on the right cheek. Hypo and hypercellular adjacent areas were mainly patternless, and the stroma was formed by thin collagen fibrils. Case 2 was a 4.8 cm mass in the anterior portion of the tongue. Microscopically it was formed by spindle cells embedded in a vascularized sclerotic collagen matrix. Some areas were hypercellular with scarce collagen fibrils. The immunohistochemical findings were similar in both cases, with strong immunoreactivity for vimentin, CD34, bcl-2, focal positivity for Ki-67 and negativity for other immunomarkers. Based on these clinical, microscopical and immunohistochemical features the final diagnosis of these two cases was SFT. Diagnosis of SFT is difficult and, although uncommon, it should be considered in the differential diagnosis of oral soft tissue tumours.

Solitary fibrous tumor of the abdominal wall: a report of two cases immunohistochemical, flow cytometric, and ultrastructural studies and literature review

Solitary fibrous tumors have been described at many extrapleural sites in recent years. However, solitary fibrous tumors arising from somatic soft tissue occur only rarely and can pose problems in the differential diagnosis from other benign or malignant soft tissue tumors. The majority of solitary fibrous tumors occurring in the somatic soft tissue have been found in the extremities and limb girdles, and the head and neck regions. There have been only eight published cases located in the abdominal wall. We herein report two female patients who developed solitary fibrous tumors of the abdominal wall that were not in association with the underlying peritoneum. Histologically, both tumors were characterized by a variety of architectural patterns, alternating hypercellular and hypocellular areas, proliferation of plump spindle cells, thick keloid-like and/or amianthoid collagen bundles, and ectatic staghorn-like vessels. Both tumors showed a diffuse strong reaction for CD34 and vimentin as well as focal positivity for bcl-2 and smooth muscle actin. A striking predominance in females was found in a literature review of solitary fibrous tumors of the abdominal wall, contrasting with other somatic soft tissue sites which show an equal gender distribution. Interestingly, expression of estrogen but not progesterone receptor was observed in both tumors. Ultrastructurally, the tumor cells displayed features of fibroblasts with dilated branching rough endoplasmic reticulum (RER) and Golgi apparatus. Both tumors assayed by flow cytometry demonstrated a diploid DNA content with an S-phase fraction of 7.9% and 11.4%, respectively. At follow up, both patients were well without evidence of recurrence or metastasis after surgical excision.

Solitary fibrous tumor of the skin

Solitary fibrous tumor (SFT) is an uncommon tumor initially reported in the pleura but recently described in other sites of the body. We report a SFT of the skin that presented as painless nodule located in the right cheek in a 56-year-old woman. Histologically, the tumor was composed of spindle-shaped cells arranged in a patternless pattern of short and narrow fascicles with interspersed bundles of thick collagen, and numerous blood vessels with a focally hemangiopericytoma-like appearance. Immunohistochemically, the tumor cells strongly expressed vimentin, CD34 and bcl-2. The lesion was excised and the patient remains well at 16-month follow-up. This case presented some diagnostic difficulty because of its unusual location, and had to be distinguished from other superficial soft tissue tumors. Recognition of SFT in the skin is important to avoid possible confusion with a variety of spindle cell neoplasms with different biologic potential.

Telomerase activity, Ki-67, cyclin D1 and A expression, and apoptosis in solitary fibrous tumors: additional features of a predictable course?

Solitary fibrous tumors (SFTs) are infrequent soft tissue neoplasms which are usually benign and surgically curable. However, their behavior is not always predictable, although several clinical and pathological criteria of malignancy have been established. In many cancers, including some soft tissue tumors, telomerase activity (TA) has been shown to be a new reliable pathological marker of malignancy. Overexpression of some cyclins is associated with higher degrees of malignancy and predictive of the clinical course. In this study, we evaluated TA, mitotic and apoptotic indices (MI, AI), and the expression of Ki-67, cyclins D1 and A in five typical and two clinicopathologically atypical SFTs, the latter two of which had also recurred. High TA was demonstrated in the two atypical cases, which also showed a higher labeling index to Ki-67, as well as higher cyclin D1 and A expression, and either none or very few apoptoses. We suggest that TA, Ki-67, cyclin expression, and AI be evaluated in SFTs as possible adjunctive pathological criteria of behavior.

Benign spindle cell tumors of the mammary stroma: diagnostic criteria, classification, and histogenesis

Purely benign mesenchymal spindle cell neoplasms of the breast are currently labeled under various terms in the literature (benign spindle cell tumor, fibroma, spindle cell lipoma, myofibroblastoma, solitary fibrous tumor, myogenic stromal tumor). The lack of strict diagnostic criteria to clearly indicate such mesenchymal neoplasms is the main reason which generated the risk of terming the same lesion under different names or, conversely, of collecting different types under the same term. Although such neoplasms exhibit morphological and immunophenotypical heterogeneity, they actually represent variations of the same tumor entity, likely arising from the uncommitted vimentin+/CD34+ fibroblasts of the mammary stroma, capable of multidirectional mesenchymal differentiation. To cover the entire spectrum of such lesions, the term "benign spindle cell tumors (BSCTs) of the mammary stroma" is advocated. BSCTs can be subtyped into four main groups by light microscopy (LM) and immunocytochemistry (ICC): fibroblastic, myofibroblastic, fibrohistiocytic, and mixed forms. A simple and practical approach to a nosologically correct diagnosis and a list of differential diagnoses are presented. The awareness of the diversity of morphological and immunophenotypical features of BSCTs of the mammary stroma, including uncommon variants, is helpful to avoid confusion with other monomorphic bland-looking benign and malignant spindle cell tumors and tumor-like lesions of the breast.

Solitary fibrous tumor in the mental region

Solitary fibrous tumor (SFT) is a rare, benign, soft tissue tumor that most commonly occurs in the pleura; however, it has recently been described in other sites of the body. To date, eight examples of oral SFT have been reported. This paper is a description of the first case of an SFT occurring as a soft tissue tumor in the mental region. Histologically, the tumor was composed predominantly of rather uniform spindle-shaped fibroblastic cells arranged in vague fascicles or in a haphazard fashion, intermingled with abundant collagen fibers. Immunohistochemically, the tumor cells were positive for CD34 and vimentin, and weakly positive for muscle actin and alpha-smooth muscle actin. The diagnosis of SFT may be difficult as this tumor shares a number of histological features with other soft tissue tumors. Awareness of its occurrence in the oral cavity is important so that confusion with other spindle cell neoplasms can be avoided.

Solitary fibrous tumor of the thyroid gland: report of seven cases

Solitary fibrous tumor is a soft tissue neoplasm initially described in the pleura but subsequently reported in a wide variety of locations. The clinical behavior is usually benign, but the existence of aggressive cases has been documented both in the pleura and in extrapleural sites. In this report clinical and pathologic features of seven solitary fibrous tumors of the thyroid gland are presented. Patients' ages ranged from 43 to 64 years (mean 52 years), and tumor sizes varied from 2 to 6 cm. Grossly, the tumors were white-tan and well circumscribed. Microscopically, there was a variegated, wavy, storiform, hemangiopericytic or desmoid-like arrangement of spindle cells. Trapped thyroid follicles within the tumor and peripheral jagged tumor infiltration among follicles were common. There was immunohistochemical reactivity for CD34, CD99, and bcl-2, and ultrastructural analysis of one tumor was consistent with a fibroblastic lineage. The differential diagnosis included other benign and malignant mesenchymal tumors of the thyroid, spindle cell follicular adenoma, Riedel's thyroiditis, the spindle cell, and paucicellular variants of anaplastic carcinoma, papillary thyroid carcinoma with exuberant nodular fasciitis-like stroma, and the spindle epithelial tumor with thymus-like differentiation. The cumulative data of 13 cases (comprised of the seven present cases and the six previously reported) suggest a benign clinical behavior for thyroid SFT.

Extra-abdominal desmoid tumor presenting as an intrathoracic tumor: case report and literature review

A case of an extra-abdominal desmoid tumor presenting as an intrathoracic tumor (intrathoracic desmoid tumor) in a 46-year-old woman is reported. The tumor originated in the left chest wall and protruded into the left pleural cavity. Simple resection was carried out. The tumor, measuring 13 x 9 x 7 cm, was solid, gray-tan in color, and covered with parietal pleura. Histologically, the tumor was composed of a hypocellular arrangement of spindle-shaped cells with a fibromyxoid background. In some areas, keloid-like hyalinized collagen fibers proliferated, and a perivascular hypercellular area was seen. Immunohistochemical analysis showed that the cytoplasms of the tumor cells were strongly positive for vimentin, and some tumor cells were positive for alpha-smooth muscle actin, but all tumor cells were negative for CD34. These findings were consistent with the characteristics of an intrathoracic desmoid tumor. The differential diagnoses, in particular solitary fibrous tumor and tumors with a myofibroblastic nature, are discussed.

Expression and localization of basic fibroblast growth factor and its mRNA in solitary fibrous tumor

Solitary fibrous tumors (SFTs) represent a distinct neoplasm that should be included in the differential diagnosis of spindle-cell neoplasms of the soft tissue. Basic fibroblast growth factor (bFGF or FGF-2) is a mitogenic and angiogenic polypeptide produced by diverse cell types, including the cells derived from normal tissue and neoplastic lesions. In this study, the expression of bFGF, vimentin, CD 34, c-kit (or CD 117), desmin, S-100 protein, and alpha-smooth muscle actin (alpha-SMA) in SFTs, hemangiopericytomas (HPC), gastrointestinal stromal tumors (GIST), and dermatofibrosarcoma protuberans (DFSP) were evaluated to assess their usefulness in the differential diagnosis of these lesions. The expression of bFGF mRNA was also examined in SFTs by in situ hybridization (ISH) using a digoxigenin-labeled bFGF oligonucleotide probe. All the SFTs, GISTs and DFSPs exhibited strong and diffuse immunoreactivity for CD34 and vimentin, and were completely negative for desmin, S-100 protein and alpha-SMA. The HPCs were positive for vimentin, but negative for CD34. In all the SFTs, strong and diffuse nuclear immunostaining was observed with bFGF antibody, contrasting with the negative staining observed in the majority of the HPCs, GISTs, and DFSPs. The bFGF mRNA was also expressed in the SFT cells. The constitutive expression of the bFGF in the SFT widens the spectrum of available markers for these tumors, providing a useful addition to their differential diagnosis in difficult cases, and contributing to the understanding of their histogenesis and molecular pathogenesis.

Large solitary fibrous tumor of the kidney: report of two cases and review of the literature

Solitary fibrous tumors are spindle cell neoplasms frequently arising in the serosal surface as well as a variety of other sites. We report two cases of large solitary fibrous tumor arising in the kidney, clinically thought to be renal cell carcinoma, in 41- and 72-year-old men. Although large in size (13.0 and 14.0 cm in greatest dimension, respectively), both lesions were 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. Immunohistochemical studies revealed reactivity for vimentin, CD34, collagen IV, and bcl-2 protein in both cases, with no staining for keratin, S-100 protein, or muscle markers, confirming the diagnosis of solitary fibrous tumor of the kidney. Solitary fibrous tumor of the kidney is rare but may present as a large mass that may be clinically confused with carcinoma or sarcoma.

Locally aggressive solitary fibrous tumor in the infraorbital region: a case report and review of the literature

We describe a case of a soft tissue neoplasm in the infraorbital region of a 31-year-old African-American man that met histologic and immunohistochemical criteria for solitary fibrous tumor. This uncommon spindle cell neoplasm was first described in the pleura, but it has since been reported in many other soft tissue locations. The lesion was locally aggressive and successfully treated by local excision. Solitary fibrous tumor can be locally destructive and can occur in a wide variety of tissues or organs; this is the seventh published case of solitary fibrous tumor in the orofacial region.

Solitary fibrous tumor: a study of cytologic features of six cases diagnosed by fine-needle aspiration

Solitary fibrous tumor (SFT) is a spindle-cell neoplasm most often presenting as a pleural-based tumor but increasingly recognized in other locations. Few reports have described the cytologic features of SFTs. Six cases of SFT diagnosed by fine-needle aspiration (3 pleura, 2 retroperitoneum, and 1 orbit) were identified in the Mayo Clinic files. The smears (Papanicolaou-stained) and corresponding histologic specimens were reviewed. Immunohistochemical staining for CD34 was performed in all cases. The cytologic findings were similar in all cases. The tumor cells were oval to polygonal, with cellularity ranging from scant to moderate. The background contained irregular ropy fragments of collagen and a few inflammatory cells. Most cells were dispersed singly, but all cases contained irregular, loose aggregates of cells enmeshed in a collagenous matrix. The nuclei were uniformly bland, with evenly distributed, finely granular chromatin. All cases were immunoreactive for CD34. SFT has distinctive cytologic features that allow diagnosis in cytologic specimens with the help of appropriate immunocytochemical stains on accompanying tissue biopsy specimens. Distinctive cytologic findings predictive of clinical behavior were not identified.

Mammary-type myofibroblastoma of soft tissue: a tumor closely related to spindle cell lipoma

Mammary myofibroblastoma is a benign breast tumor, with a reported predilection for older men. It is composed of fascicles of spindle cells having features of myofibroblasts, with intervening hyalinized collagenous stroma and a variably prominent component of adipose tissue. The spindle cells characteristically express both CD34 and desmin. Herein, we report the clinicopathologic features of nine tumors that were morphologically and immunohistochemically identical to myofibroblastoma of breast; however, they arose in subcutaneous soft tissue at extramammary sites. The study group comprised seven men and two women with an age range of 35-67 years (median 53 years). Lesions presented as either a slowly growing painless mass or were incidental findings at the time of surgery. The site distribution was as follows: inguinal/groin area (five cases) and one case each in posterior vaginal wall, buttock, anterior abdominal wall, and mid-back. Tumor size ranged from 2 to 13 cm (median 6 cm), and all lesions were well circumscribed. Eight tumors had a component of adipose tissue (ranging from 10% to 60%), within which some variation in adipocyte size was often seen. One case showed epithelioid cytomorphology and three cases showed rare atypical or multinucleated cells. Focal myxoid stromal change was seen in four cases. Tumor cells were positive for desmin (9 of 9 cases), CD34 (8 of 9 cases), and occasionally positive for smooth muscle actin (3 of 9 cases). Lesions were marginally excised with no recurrences to date, although follow-up is very limited. Lesions with morphologic and immunophenotypic features similar to myofibroblastoma of breast can arise at extramammary sites, with an apparent predilection for the inguinal area of older men. Both mammary and extramammary lesions show morphologic overlap with spindle cell lipoma and are likely closely related.

Solitary fibrous tumours of the meninges: case series and literature review

We report four new cases of meningeal Solitary Fibrous Tumour (SFT). Two patients presented with raised intracranial pressure from posterior fossa SFT, and the third developed hemiparesis and dysphasia due to a large lesion that originated in the left middle cranial fossa. These were successfully excised and the patients remain well at follow-up of between 1 and 3 years. The fourth patient, a 71-year-old man, suffered an intracerebral haemorrhage and later died from a malignant SFT that had invaded the falx cerebri, superior sagittal sinus, and brain. This is the first description of a locally aggressive meningeal SFT with multiple atypical histological features. The 31 previously reported cases of meningeal SFT are reviewed. They occur at all ages and may be relatively more common in the posterior fossa and spine. Intracranial SFT originate from the dura and are probably indistinguishable from meningiomas on imaging and at surgery. In contrast, approximately two-thirds of spinal SFT have no dural attachment. Histologically, SFT are spindle-cell neoplasms with a characteristic immunohistochemical profile of CD34, vimentin, and bcl-2 positivity. Data on outcome for patients with meningeal SFT are limited. At other sites, however, extent of resection is the most important prognostic factor, and invasion or metastasis can occur with histologically benign SFT. Meningeal SFT should, therefore, be excised as completely as possible and followed carefully in the long-term.

Solitary fibrous tumor of the oral soft tissues: a clinicopathologic and immunohistochemical study of 16 cases

We describe the clinicopathologic and immunohistochemical features of 16 solitary fibrous tumors (SFTs) originating within the oral soft tissues. There were 10 women and six men with a mean age at diagnosis of 56 years. In all cases the tumors were slow-growing, asymptomatic, submucosal growths of variable size and duration. The buccal mucosa was involved in 12 cases, and the tongue and lower lip were affected in two cases, respectively. Thirteen tumors developed on the left side of the mouth. Follow-up information was available in 10 cases and averaged 44.7 months, with no evidence of recurrence or metastasis. All 16 tumors were well circumscribed and demonstrated histologic features that were invariably benign. In all cases they were composed of an admixture of alternating hypercellular and hypocellular, collagenous zones; haphazardly arranged, cytologically bland spindle and ovoid cells that in areas were intimately intermixed with collagen; a prominent vasculature; and perivascular hyalinization. Immunohistochemically, the tumors were consistently positive for CD34, bcl-2, factor XIIIa, and vimentin, whereas 75% of the tumors were reactive for CD99. To further define the clinicopathologic profile of intraoral SFT, we include a review of the previously reported cases. We also include a comparison and brief review of the clinicopathologic and immunohistochemical features of other spindle cell tumors of the oral cavity, from which SFTs must be differentiated.

True hemangiopericytoma of the nasal cavity

Two cases of nasal tumors with pericytic myoid differentiation are reported. The tumors occurred in a 77-year-old woman and a 60-year-old man as polypoid lesions covered by normal mucosa. Histologically, the tumors were composed of uniform short spindle or stellate cells with indistinct cell borders arranged in narrow and short fascicles. Numerous blood vessels of various sizes were common in both cases. The tumor cells of both cases stained intensely with anti-vimentin and anti-actin antibodies, but not with anti-desmin, CD34, or anti-high-molecular-weight caldesmon antibodies. Ultrastructural examination revealed well-developed actin thin filaments with dense bodies, subplasmalemmal plaques, intercellular junctions, and irregular discontinuous basement membranes. These histopathologic features suggest true pericytic differentiation of the tumors (true hemangiopericytoma), unlike soft tissue-type hemangiopericytoma. Generally, sinonasal hemangiopericytomas are subdivided into soft tissue-type hemangiopericytomas and true hemangiopericytomas identical to the cases presented here. Soft tissue-type hemangiopericytomas are frequently highly aggressive, whereas true hemangiopericytomas show localized benign behavior. Sinonasal true hemangiopericytomas should be strictly differentiated from soft tissue-type hemangiopericytomas.

Spindle cell epithelioma of the vagina shows immunohistochemical staining supporting its origin from a primitive/progenitor cell population

Spindle cell epitheliomas of the vagina (SCEVs) coexpresses epithelial and mesenchymal markers and were first described as a "mixed tumors of the vagina." However, unlike mixed tumors of other organs, which are believed to originate from myoepithelial cells, SCEVs neither immunohistochemically nor ultrastructurally show features of myoepithelial cells. The present expanded battery of immunohistochemical stains is presented on this rare tumor, including cytokeratin AE1/AE3, CK7, CK20, S100 protein, epithelial membrane antigen, alpha-smooth muscle actin, desmin, CD34, CD99, Bcl-2, vimentin, estrogen and progesterone receptors, and Ki-67. There was minimal expression of alpha-smooth muscle actin and negative staining with S100 protein, with coexpression of cytokeratins and vimentin and expression of estrogen and progesterone receptors, as previously reported in SCEVs. In addition, diffuse expression of CD34, CD99, and Bcl-2 immunohistochemical stains was found, which has not previously been reported. The coexpression of CD34, CD99, and Bcl-2 in SCEVs is consistent with its origin from a primitive/progenitor cell population.

Myofibroblastoma and solitary fibrous tumour of the breast: histopathologic and immunohistochemical studies

Thirteen mesenchymal tumours of the breast were reviewed histologically and immunohistochemically. Nine tumours (male:female ratio 5:4, average age 64 years) were classified as myofibroblastomas and presented as a single nodule (four) or a multilobular mass (five). They were composed of elongated cells with vesicular nuclei showing grooves, intranuclear inclusion, and small but conspicuous nucleoli resembling myofibroblasts seen in scar tissue. In six tumours, hypercellular zones alternated with paucicellular, hyalinized areas. The collagen pattern was dense, diffuse, and brightly eosinophilic in all neoplasms. The tumour cells were positive for desmin, actin, and vimentin in all nine lesions, and in six tumours a focal CD 34 positivity was also demonstrated. Four tumours (four female patients, average age 75 years) were classified as solitary fibrous tumours and consisted of well-circumscribed nodules. They were characterized by a monomorphic population of thin, spindled to ovoid cells with finely dispersed chromatin and inconspicuous nucleoli. The pattern of the collagen in these tumours was one of thick, brightly eosinophilic bands. These four tumours were negative for all markers tested except vimentin and CD 34. Although myofibroblastomas and solitary fibrous tumours of the breast share many morphologic features, there are enough differences in their cytologic composition and, most importantly, in their immunohistochemical profile to consider them as distinct entities.

CD34, CD117, and actin expression in phyllodes tumor of the breast

BACKGROUND

This study investigated the immunophenotypic patterns of CD34, CD117 (a product of the c-kit proto-oncogene), and actin (HHF35) in benign and malignant phyllodes tumors (PTs). We correlated the expression of CD34, CD117, and actin with histopathological grade.

MATERIALS AND RESULTS

We analyzed 19 cases (7 benign and 12 malignant cases) of PTs using immunohistochemical analysis. Six of 7 benign PT stromal lesions stained positively for CD34, while only 3 of 12 cases of malignant PT were focally CD34 positive (P = 0.0106). Only 1 of the 7 benign PTs stromal lesions expressed CD117. Nine of the malignant PTs were composed CD117-positive fibroblasts. This result demonstrated that CD117 expression is associated with the malignant potential of PTs (P = 0. 0106). Actin (HHF-35) expression was found in 8 of 12 cases of malignant PTs (P = 0.027), but in only 1 of 7 cases of benign PTs. Actin expression was significantly (P = 0.04) correlated to frequent mitotic activity (>5 mitoses per 10 high-power fields). The immunophenotypic markers were not related to tumor size. Additionally, we sequenced part of the juxtamembrane region of the c-kit proto-oncogene and found point mutations in two malignant PTs.

CONCLUSION

Our results demonstrated that expression of CD34 was associated with benign PTs, while CD117 and actin were preferentially expressed in malignant PTs. Our results implied that these immunohistological markers might be used for the histopathological grading of PTs.

Metastatic solitary fibrous tumor of the meninges. Case report

Solitary fibrous tumor (SFT) is a unique tumor composed of interstitial dendritic cells that was first described in the thorax and subsequently reported in diverse organs. Extrathoracic SFTs are predominantly benign but rare malignant cases have been documented. In the nervous system, SFT has been described as a meningeal lesion although all 14 previously reported cases were benign. The authors report the first case of a meningeal SFT occurring in a 55-year-old woman. The tumor first presented as a meningeal lesion that after three recurrences over a 10-year period metastasized to the soft tissues and lungs. The potentially malignant nature of cranial SFTs, especially those with atypical histological features and high mitotic counts, should be recognized.

Orbital and extraorbital giant cell angiofibroma: a giant cell-rich variant of solitary fibrous tumor? Clinicopathologic and immunohistochemical analysis of a series in favor of a unifying concept

The clinicopathologic and immunohistochemical features of one orbital and nine extraorbital soft tissue lesions, the morphology of which overlaps with giant cell angiofibroma and solitary fibrous tumor, are presented. There were 3 male and 7 female patients. Age at diagnosis ranged from 18 to 81 years (median: 45 yrs). Development of a mass was the main presenting symptom. For two patients, the lesion had been evident for several years before excision. Extraorbital tumors were located in the head and neck area (3), back (3), retroperitoneum (1), hip (1), and vulva (1). Tumor size ranged from 1.3 cm to 11 cm (median: 4.5 cm). The lesions presented grossly as well-demarcated, unencapsulated soft tissue masses. Histologically, they were characterized by the presence of alternating cellular and sclerosing areas, keloidal collagen deposition, round- to staghorn-shaped, thick-walled vessels and multinucleated giant stromal cells often lining pseudovascular spaces. Cellular areas were composed of non-atypical spindle to round cells set in a variably collagenous background. Mitotic activity ranged from 1 to 3 mitoses/10 high-power fields. Immunohistochemical studies showed positive staining of the spindle/round cells and multinucleated stromal cells invariably for vimentin, CD34, CD99, and mostly for bcl-2 but negative for muscle specific actin, desmin, CD31, CD117 (c-kit), and inhibin. Occasionally, focal reactivity was observed for smooth muscle actin, S-100 protein, epithelial membrane antigen, and keratin. Treatment consisted of simple tumorectomy in eight patients and wide excision in two. Follow-up information for eight patients (range: 7-32 mos; median: 14 mos), including four with microscopically positive surgical margins, showed no recurrence. These lesions share the clinical, pathologic, and immunohistochemical features of giant cell angiofibroma and solitary fibrous tumor, supporting the view that these tumors are closely related. In addition, it shows that giant cell angiofibroma occurs equally in both sexes and has a wider distribution than initially thought, developing even more often in extraorbital locations than in the orbit.

What are the CD34+ cells in benign peripheral nerve sheath tumors? Double immunostaining study of CD34 and S-100 protein

To determine whether CD34 expression in nerve sheath lesions was found in a unique cell population or in a subset of nerve sheath cells, we performed double immunohistochemical staining using a standard avidinbiotin complex method with 2 separate color developing systems. We studied 40 neurofibromas and 16 neurilemomas. All lesions strongly expressed S-100 in nuclei and cytoplasm. CD34 was detected in cells having ameboid dendritic cytoplasm present in greatest numbers in Antoni B zones of neurilemomas, myxoid zones of neurofibromas, at the periphery of lobules in both tumor types, and condensed in apposition to perineurium. The CD34+ cells also were detected in normal nerves. They were infrequent in Antoni A zones of neurilemomas. No dual S-100 and CD34 expression was seen. This double immunostaining confirms the presence of a CD34-reactive non-Schwannian cell type in these neural neoplasms. As the CD34+, S-100-negative cell population is present also in normal nerves and infrequently seen in the areas of cellular neoplastic Schwann cells, CD34+, S-100-negative cells in peripheral nerve sheath tumors most likely are nonneoplastic and may have a supportive function.

Solitary fibrous tumour of the orbit. Report of a new case

PURPOSE

Solitary fibrous tumour (SFT) of the orbit is a very rare lesion that may be misdiagnosed as fibrous histiocytoma, haemangiopericytoma, or other orbital tumour. We studied a case of SFT of the orbit in a 35-year-old woman.

METHODS

The patient, with a 1-year history, reported a 'pressure' sensation behind her right eye, but no pain, vision changes, or other associated symptoms. Ocular examination was normal. Magnetic resonance imaging (MRI) showed a well-circumscribed medial mass in the right orbit. The tumour was excised.

RESULTS

The tumour was a cellular spindle-cell neoplasm with a storiform pattern. The tumour cells were spindle-shaped with bland nuclei and rare mitoses. Immunostaining was positive for vimentin and CD34, but negative for cytokeratin (AE1-AE3), EMA, desmin, smooth muscle actin, S-100, CD31, CD45 and bcl-2.

CONCLUSION

SFT can infrequently involve the orbit. The tumour must be removed entirely to avoid recurrences. Careful and continued follow-up is important because orbital recurrence may occur several years after the excision of the primary tumour.

Expression of CD34, bcl-2, and kit in inflammatory fibroid polyps of the gastrointestinal tract

The histogenesis of inflammatory fibroid polyps (IFP) of the gastrointestinal tract, focused on the cell of origin of the stromal cells, is a controversial subject. The reported CD34 reactivity in gastric IFP has implied a histogenetic relationship with a variety of CD34-reactive tumors, including gastrointestinal stromal tumors (GIST). In addition to bcl-2, the majority of GIST has expressed Kit, suggesting an origin in interstitial cells of Cajal (ICC), which are selectively localized around nerve plexuses. Gastric (12) and colonic (two) IFP from 13 patients were studied, using antibodies against CD34, bcl-2, and Kit. IFP expanded muscularis mucosae with prominent vascular channels, inflammatory infiltrates, proliferating stromal cells, and extracellular matrix material. Eleven gastric IFP exhibited concentric stromal proliferations (CP), particularly, around vessels, glands, and muscle bundles. Their stromal cells were CD34 reactive, bcl-2 nonreactive, and Kit nonreactive and showed fibroblast-like appearances with thin, long cytoplasmic processes. In contrast, one gastric and two colonic IFP showed no CP, and their stromal cells were CD34 nonreactive, bcl-2 nonreactive, and Kit nonreactive. IFP with CP may have a different histogenesis from IFP without CP. IFP with CP may originate from a subpopulation of dendritic interstitial cells other than ICC, predominantly localized around blood vessels and muscle fibers in muscularis mucosae of the stomach.

Collagenous fibroma (desmoplastic fibroblastoma): a unique presentation as a goiter in an 88-year-old man

Collagenous fibroma (desmoplastic fibroblastoma) is a recently described entity in the medical literature. This entity has been reported in various locations, including the upper extremities, posterior neck, upper back, lower extremities, abdominal wall, and hip. We report an interesting case of an 88-year-old man who presented with an apparent goiter involving the right anterolateral neck. Histologic studies revealed a well-circumscribed, paucicellular lesion composed of stellate and spindle-shaped fibroblasts separated by bundles of collagen. No mitotic figures, necrosis, or calcification was observed. The stellate and spindle-shaped cells were positive for vimentin and focally positive for desmin, indicating myofibroblastic differentiation. Our case exemplifies the diagnostic difficulties that these tumors may pose from the clinical and radiologic standpoint when they clinically present as a goiter.

Atypical solitary fibrous tumor of the vulva

An atypical solitary fibrous tumor (SFT) was encountered as a slow-growing, 15-cm, well-demarcated, vulvar tumor in a 70-year-old woman. The tumor was highly cellular and composed predominantly of hemangiopericytomatous and capillary hemangioma-like proliferations and short fascicular arrangements of spindled cells. Multinucleated giant cells and tumor necrosis also were present. The tumor cells were positive for vimentin, CD34, progesterone receptors, and bcl-2 and were diploid by flow cytometry. The patient was well without disease 9 months after surgery. Awareness of the occurrence of atypical SFT in the vulva is important so that confusion with other neoplasms can be avoided.

Solitary fibrous tumor of the thoracic spine. Case report and review of the literature

Solitary fibrous tumor (SFT) is a neoplasm first described as a tumor of mesenchymal origin involving soft tissues. The authors provide a review of the literature with detailed pathological analysis and radiological description of SFTs involving the central nervous system. The authors report a rare case of a SFT of the thoracic spine in an adult man presenting with myelopathy. Magnetic resonance imaging revealed a well-circumscribed, intradural, extramedullary mass at the T2-3 level. Histological examination demonstrated a proliferation of predominantly spindle-shaped cells with a collagen-matrix background. Immunohistochemical staining was positive for vimentin and CD34 and negative for S-100 and epithelial membrane antigen with an MIB-1 labeling index of 2.6%. Review of the literature revealed 10 cases in which this tumor, frequently found in the pleura, was involved in the central nervous system. Although rare and their clinical significance as yet unknown, SFTs may be considered in the differential diagnosis of intradural spinal cord lesions. The natural history is also unknown, but these tumors appear to be biologically benign.

Vascular endothelial growth factor receptor-3 (VEGFR-3): a marker of vascular tumors with presumed lymphatic differentiation, including Kaposi's sarcoma, kaposiform and Dabska-type hemangioendotheliomas, and a subset of angiosarcomas

Recently, a novel monoclonal antibody to vascular endothelial growth factor receptor 3 (VEGFR-3), a tyrosine kinase receptor expressed almost exclusively by lymphatic endothelium in the adult, has been shown to react with a small number of cases of Kaposi's sarcoma (KS) and cutaneous lymphangiomas. We sought to extend these studies to a large number of well-characterized vascular neoplasms to evaluate diagnostic uses of this antibody and to determine whether it defines them in a thematic fashion. Formalin-fixed, paraffin-embedded sections from 70 vascular tumors were immunostained with antibodies to VEGFR-3 von Willebrand factor (vWF), and CD31. Anti-VEGFR-3 was positive in 23 of 24 KS, 8 of 16 angiosarcomas (AS), 6 of 6 kaposiform hemangioendotheliomas, 4 of 4 Dabska tumors, and 2 of 13 hemangiomas. Positively staining angiosarcomas were characterized either by a prominent lymphocytic component, a hobnail endothelial cell similar to that encountered in the Dabska tumor, or spindled areas resembling KS. No VEGFR-3 expression was noted in any cases of epithelioid hemangioendothelioma, pyogenic granuloma, littoral angioma, or stasis dermatitis. vWF expression was seen in 10 of 13 KS; 13 of 14 AS; 4 of 5 kaposiform hemangioendotheliomas; and all Dabska tumors, hemangiomas, lymphangiomas, epithelioid hemangioendotheliomas, vascular malformations, stasis dermatitis, and splenic littoral angiomas. CD31 expression was present in 12 of 13 KS, 13 of 14 AS, and in all other cases. Expression of VEGFR-3 is a very sensitive marker of KS, kaposiform, and Dabska-type hemangioendotheliomas, suggesting that all show at least partial lymphatic endothelial differentiation. Expression of VEGFR-3 does not reliably discriminate KS from AS. However, the expression of VEGFR-3 by certain AS having Kaposi-like areas, a prominent lymphocytic infiltrate, or hobnail endothelium may define subset(s) having phenotypic, if not pathogenetic and biologic, differences.

Solitary fibrous tumor of the vagina

We report of a solitary fibrous tumor (SFT) of the vagina and discuss the differential diagnosis. This is the first SFT documented, to our knowledge. SFTs should be included in the differential diagnosis of fibroblastic, myofibroblastic, and neural lesions of the skin, subcutaneous tissue, and mucosa and can be distinguished from other spindle cell neoplasms at those sites.

Angiomyofibroblastoma of the Male Perineum: An Unusual Location for a Rare Lesion

We report a case of angiomyofibroblastoma (AMF)-like tumor of the perineum in a 54-year-old man. The asymptomatic lesion measured 3 cm and appeared as a tan homogeneous mass. Histologically, it appeared as a circumscribed nodular spindle cell proliferation with alternating cellular and hypocellular areas. The spindle cells exhibited minimal nuclear pleomorphism and scanty mitotic activity. Focally, some cells were epithelioid. Large blood vessels were present, with perivascular fibrosis. The spindle cells expressed vimentin, but not desmin, actin, S100, or CD34. These features were similar to those of AMF as initially reported in the vulva. A perineal localion of this lesion in a male has not been reported in the literature, to the best of our knowledge. Int J Surg Pathol 8(1):79-82, 2000

Giant cell angiofibroma of the buccal mucosa

We report a case of a patient with a recently described entity (giant cell angiofibroma) occurring in the oral cavity. A submucosal solid tumor arising in the right buccal mucosa of a 46-year-old woman was histologically characterized by a patternless spindle-cell proliferation within a generally myxoid stroma containing areas of perivascular sclerosis. Numerous multinucleated giant cells of the floret type were present. Immunohistochemically, the tumor cells and multinucleated giant cells exhibited positivity for CD34. To the best of our knowledge, this is the first report of a giant cell angiofibroma arising in the oral cavity.

Collagenous fibroma (desmoplastic fibroblastoma) presenting as a parotid mass

We describe the case of a 50-year-old man who was found to have a painless, slow-growing parotid mass of 10 months duration. At surgery, a well-delimited, lobulated 4x5-cm tumor was located on the deep lobe of the left parotid gland, adhering to the parotid sheath and masseteric fascia. Follow-up 6 years later has shown no evidence of recurrence. Cardinal morphologic features included multiple nodules of sparsely distributed stellate-or spindle-shaped fibroblasts within a collagenous or myxocollagenous stroma. Fascial involvement and entrapment of salivary gland were focally identified at the edges. Tumor cells were diffusely positive for vimentin with faint focal staining for alpha-smooth muscle actin. These findings satisfied the diagnostic criteria for collagenous fibroma (desmoplastic fibroblastoma). Ours represents the first report of this tumor type mimicking a parotid tumor.

Differential expression of CD34 and Ki-M1p in pleomorphic fibroma and dermatofibroma with monster cells

Pleomorphic fibroma (PF) and dermatofibroma with monster cells (DFMC) are characterized by the presence of numerous cells with large atypical nuclei. Despite cytologic similarities, the two entities are likely to be unrelated, but their histogenesis is poorly understood. In this study, we examined six cases of PF and eleven cases of DFMC by immunohistochemistry using antibodies against vimentin, alpha-smooth muscle actin, S-100 protein, CD34, factor XIIIa, and the pan-monocytic marker Ki-M1p. Strong vimentin expression was seen in all tumors, whereas none of them expressed S-100 protein. PF consistently exhibited CD34 staining but appeared to be depleted of Ki-M1p positive cells compared with the surrounding normal skin. Conversely, all cases of DFMC contained numerous Ki-M1p positive cells including atypical multinucleate cells, but virtually no CD34 reactivity was observed. A weak staining for alpha-smooth muscle actin was occasionally seen in a subset of the cells of both entities. Our results indicate that PF and DFMC are histogenetically distinct entities that may arise from two different types of dermal dendritic cells defined by their reactivity for CD34 and Ki-M1p, respectively. Immunohistochemistry using these two antibodies permits an easy and reliable discrimination between PF and DFMC.

Lipomatous hemangiopericytoma: a morphologically distinct soft tissue tumor

Hemangiopericytoma of soft tissue is a controversial pathologic entity. The relative nonspecificity of the characteristic branching capillary pattern and cytologic features of the constituent cells, in addition to the lack of a distinct immunohistochemical staining profile, has resulted in uncertainty and a lack of consensus regarding this subgroup of tumors. Notwithstanding the doubt surrounding this entity, a morphologically unique variant, designated lipomatous hemangiopericytoma, was reported in 1995. To our knowledge, there have been no further reports of these tumors since the original description. We describe a lipomatous hemangiopericytoma that arose within the thigh of a 41-year-old woman. The tumor presented as a slowly enlarging, minimally tender, pulsatile mass. The tumor was completely excised and was found to be composed of an admixture of typical hemangiopericytoma and predominantly mature adipose tissue. Unlike previous descriptions of this entity, the current example exhibited a full range of adipocyte differentiation, including many multivacuolated adipocytes of variable size with characteristic nuclear scalloping (lipoblast-like cells). The mitotic count was less than 2 per 10 high-power fields examined. The clinical course has been benign during the short follow-up period. We discuss the pathologic features, including the immunohistochemical staining profile and ultrastructural appearance of this distinctive tumor, and briefly discuss the relationship between hemangiopericytoma and solitary fibrous tumor of soft tissue, a neoplasm with many clinical and pathologic similarities.

Solitary fibrous tumor of the buccal mucosa: report of a case with immunohistochemical studies

We describe a case of a solitary fibrous tumor of the buccal mucosa and report the results of immunohistochemical studies of the lesion. Solitary fibrous tumors are extremely rare in the intraoral region. These tumors are generally difficult to diagnose because of their broad range of morphologic characteristics. We regard the expression of CD34 within the appropriate clinical and morphologic setting, in the absence of reactivity for other specific markers of differentiation, as evidence supporting the diagnosis of solitary fibrous tumor.

A solitary fibrous tumor in the perianal region with a 13-year follow-up: report of a case

A case of a solitary fibrous tumor (SFT) of the perianal region in a 62-year-old man is reported herein. The patient had undergone an abdominoperineal excision of the rectum for an anorectal tumor 13 years previously, and had been referred to our hospital for a perineal mass. Computerized tomography and angiography revealed a markedly hypervascular tumor measuring 11 x 8 cm in size in the pelvic cavity. After preoperative radiotherapy (total 58 Gy) and the embolization of the feeding arteries, he underwent an en bloc excision of the tumor. Microscopically, the tumor was composed of spindle shaped cells with a "patternless" arrangement in a collagenous background. There was immunohistochemical evidence that these cells were strongly positive for CD34, thus suggesting the tumor to be SFT. The previously resected anorectal tumor showed similar histological and immunohistochemical findings. The patient's recovery was uneventful.

Extraorbital giant cell angiofibroma

A number of intriguing fibrovascular mesenchymal proliferations with benign or low grade malignant potential have recently been described. Giant cell angiofibroma was introduced as an entity by Dei Tos et al. in 1995 and initially considered to be a lesion of the orbit. We describe an extraorbital example, indicating that giant cell angiofibroma is not confined to the orbit. Immunologically, giant cell angiofibroma is positive for CD 34, bcl-2 and vimentin, and negative for epithelial and muscle markers, and S-100. The tumor shares several morphological and immunological properties with giant cell fibroblastoma and solitary fibrous tumor, yet it features a histology sufficiently characteristic to allow its categorization as a separate entity. The recommended treatment is complete but conservative excision. Metastases have not been reported.

Solitary fibrous tumor of the skin

Solitary fibrous tumor (SFT) is an uncommon mesenchymal tumor that typically arises in the pleural cavity. Comprised of spindled cells characteristically arranged in diverse architectural patterns, SFT histologically simulates a variety of benign and malignant mesenchymal tumors. The diagnosis of SFT has been refined by the availability of newer immunohistochemical markers such as CD-34 and factor XIIIa, facilitating the identification of SFTs arising in multiple extrapleural sites, including the skin. We describe three cases of primary cutaneous SFT, review the literature, and discuss the histologic and immunohistochemical differential of other cutaneous tumors that SFT can mimic.

Solitary fibrous tumor of the pleura: a cytogenetic study

A solitary fibrous tumor of the pleura was studied. Its karyotype was 46,XY,t(6;17) (p11.2;q23),ins(9;12)(q22;q15q24.1),inv(16)(p13.1q24). The rearrangement of 12q13-15 was also described in a subset of hemangiopericytomas of soft tissue and meninges. Because both types of tumors are morphologically and immunophenotypically quite similar, and because some of them share rearrangement of 12q13-15, the possibility of their histogenetical relatedness should be considered.