Solitary fibrous tumors of the skin: a clinicopathologic study of 10 cases and review of the literature

Surgical removal of an unusual huge solitary fibrous tumor in the mediastinum: a case report

BACKGROUND

Intrathoracic Solitary Fibrous Tumors (SFT) mainly arise from the pleura; however, these tumors may also originate from the mediastinum. We present a rare case of posterior SFT extending to several mediastinal sites and with an unusual large size, successfully treated with surgical resection.

CASE PRESENTATION

A 66-year-old female presented with an initial manifestation of ambiguous pain in the chest and dysphagia and later developed pitting edema in both lower extremities and cachexia five months before admission. Chest imaging confirmed a mediastinal mass (17 × 15 × 8 cm) which was surgically removed. Immunohistochemistry confirmed the diagnosis of a solitary fibrous tumor with positive B-cell lymphoma 2, STAT6, and CD99, negative S100 and smooth muscle actin, and low levels of Ki67 (5-7%). The patient's follow-up course was unremarkable.

CONCLUSION

Mediastinal SFTs may grow extremely huge, with the potential to invade multiple adjacent sites. Surgical removal of the tumor remains the mainstay of treatment in these cases.

Recurrent malignant solitary fibrous tumor of the scalp: a case report and literature review

Solitary fibrous tumor (SFT) is a rare type of mesenchymal neoplasm that first was discovered in the pleura but can also affect the peritoneum, lungs, mediastinum, and skin. Cutaneous malignant SFT is an extremely rare tumor that resembles dermatofibrosacoma protuberance (DFSP) histologically and immunohistochemically. Herein, we describe a case of malignant SFT that presented as a recurrent mass on the scalp. The first lesion was totally excised one year before recurrence and was diagnosed as a DFSP based on the histopathology and cluster of differentiation 34 immunostaining positivity. Re-examination of the previously examined specimen was considered. Activator of transcription 6 positivity was also detected in the tissue, confirming the diagnosis of a recurrent malignant SFT rather than DFSP. There was no evidence of recurrence, locoregional, or distant metastases at six months after lesion removal with a safety margin.

Cutaneous solitary fibrous tumor: Report of three cases with review of histopathological mimics

Solitary fibrous tumor (SFT) is a relatively uncommon spindle cell mesenchymal neoplasm that is most often based on the pleura but may rarely arise in extrapleural locations, including the skin. Herein, we describe three cases of cutaneous SFTs. SFT is characterized by epithelioid and spindle cells arranged in random patterns with focal prominent stromal collagen and pericytomatous vessels. Immunohistochemical evaluation is required for definitive distinction of SFT from other benign and malignant cutaneous spindle cell neoplasms. Although aggressive biologic behavior is uncommon, accurate diagnosis of it is required for prognostication and counseling. CD34, bcl-2, and CD99 stains are positive in SFT, but not specific. STAT6 is the most sensitive and specific immunohistochemical marker to confirm diagnosis of SFT.

Supraorbital Craniotomy for Sellar Solitary Fibrous Tumor: Operative Technique and Literature Review

OBJECTIVE

Solitary fibrous tumors (SFT) are rare, locally aggressive, mesenchymal neoplasms that pose both diagnostic and operative challenges. In this review of the literature, data were collected from all previously described sellar and suprasellar SFTs to date, with special attention paid to presenting symptoms, surgical technique performed, recurrence status, and adjuvant radiotherapy or chemotherapy, among others.

METHODS

A review of prior sellar and suprasellar SFTs was performed. Eleven cases of SFTs in the sellar and suprasellar regions were identified. We considered age and sex, along with case-specific information, such as presenting symptoms, surgical approach taken, number of resections, recurrence information, and adjuvant therapy.

RESULTS

All cases including ours presented with visual deficits, ranging from blurry vision to complete bilateral visual loss. Endocrine hormonal abnormalities occurred in nearly all patients (90%.) Craniotomy was performed more often than endonasal transsphenoidal resection of tumors, 42% versus 33%, respectively.

CONCLUSIONS

SFTs are slow-growing fibroblastic mesenchymal neoplasms that comprise <2% of all intracranial tumors. They are even more infrequently found in the sellar/suprasellar region, with our case being the 12th reported case of such and the first only to use supraorbital craniotomy as a resection strategy. Multimodal therapy consisting of safe gross total resection, radiosurgery, and/or chemotherapy provides the best possible results for these rare and locally aggressive entities.

A Case of Solitary Fibrous Tumor of Subungual Region

Solitary fibrous tumor (SFT) is a relatively uncommon mesenchymal neoplasm that usually arises in the pleura, but also has been reported in numerous extrapleural locations, including cutaneous site. The skin lesion presents as a circumscribed nodule or tumor, mainly on the head and neck. A 41-year-old male presented with 6 months history of nail lesion without symptom on the left third finger. The lesion is slightly yellowish discoloration with subungual erythematous nodule and distal onycholysis. Biopsy specimen from the nail lesion showed the spindle cells form patternless pattern with hypercellular and hypocellular area. And small blood vessels and dilated vascular spaces were present. The result of special stain for specimen showed that positive for CD34, Bcl-2, and CD99 but negative for S-100, FactorXIIIa, and smooth muscle action. Recognition of this uncommon location of SFT is important because of possible confusion with other subungual tumors, including glomus tumor, fibroma and other fibrohistiocytic tumors like dermatofibrosarcoma protuberans, superficial acral fibromyxoma and cellular digital fibroma. Here in, we report a case of SFT of subungual region. We think this case is interesting because of uncommon location and may be helpful to more understand the character of this disease.

Primary Cutaneous Solitary Fibrous Tumor on the Back

Solitary fibrous tumors (SFT) are uncommon mesenchymal tumors. SFT have several synonyms including localized fibrous tumor, benign mesothelioma, localized fibrous mesothelioma, and submesothelial fibroma. SFT usually occur in the pleura or other serosal surfaces, but SFT can also develop in extrapleural areas including the nasal cavity, orbit, retroperitoneum, and pelvis. Cutaneous SFT is extremely rare, and more likely to occur in the head and neck region. Histologically, this tumor can mimic a variety of benign and malignant tumors such as dermatofibroma, dermatofibrosarcoma protuberans, spindle cell lipoma or other mesenchymal tumors. Most cases of SFT show non-aggressive clinical courses, with low recurrence rates. Herein, we describe a case of primary cutaneous SFT which presented with huge mass on the back.

Nervous System Hemangiopericytoma

The management of patients harboring central nervous system (CNS) hemangiopericytomas (HPCs) is a partially answered challenge. These are rare locally aggressive lesions, with potential for local recurrence, distal neural metastasis (DNM), and extraneural metastasis (ENM). Resection, when feasible, remains the initial treatment option, providing histological diagnosis and immediate relief of tumor-related mass effect. Patients receiving surgery alone or surgery and external beam radiotherapy (EBRT) show improved overall survival (OS) and progression-free survival as compared to those undergoing a biopsy alone (p = 0.01 and p = 0.02, respectively). Yet, in many instances, patient and tumor-related parameters preclude complete resection. EBRT or stereotactic radiosurgery (SRS) shares a significant role in achieving local tumor control, not shown to impact OS in HPC patients. The benefits of SRS/EBRT are clearly limited to improved local tumor volume control and neurologic function, not affecting DNM or ENM development. SRS provides acceptable rates of local tumor volume control coupled with treatment safety and a patient-friendly apparatus and procedure. Single-session SRS is most effective for lesions measuring <2 cm in their largest diameter (10 cm3 volume), with prescription doses of at >15 Gy. Systemic HPC disease is managed with various chemotherapeutic, immunotherapeutic, and anti-angiographic agents, with limited success. We present a short discussion on CNS HPCs, focusing our discussion on available evidence regarding the role of microsurgical resection, EBRT, SRS, chemotherapy, and immunotherapy for upfront, part of adoptive hybrid surgery approach or for recurrent HPCs.

Superficial Solitary Fibrous Tumor: A Series of 26 Cases

While superficial (cutaneous/subcutaneous) solitary fibrous tumor (SFT) have been described, definitive diagnosis is difficult due to overlapping features with other tumors. We describe the largest series to date of superficial SFT. For inclusion, SFT had to arise in dermis or subcutis. Twenty-six cases were identified. Patients ranged from 16 to 80 years (mean, 47 y) with a marked female predominance (19 F; 7 M). Tumors involved the head (11), thigh (7), back (3), shoulder (2), upper arm (1), ankle (1), and great toe (1). Mean size was 2.9 cm (range, 1.0 to 7.0 cm). The majority (n=19) had typical histologic features (cellular SFT) with irregular fascicles of spindled cells, staghorn-like blood vessels, and variable amounts of collagen. Necrosis was evident in 3 cases (all <25%). Mitotic activity ranged from 0 to 10 mitotic figures/10 high-power fields (mean, 2 mitotic figures/10 high-power fields). Seventeen of the 18 were positive for STAT6, whereas 21/22 expressed CD34. All were low risk (23/23) by proposed criteria (Demicco and colleagues), including 2 cases with malignant histology. Three could not be risk stratified due to lack of information on tumor size. Follow-up, available on 7 cases, showed no recurrence/metastasis (mean follow-up, 100 mo; range, 2 to 241 mo). Cutaneous SFT are more common in women and most often involve the head. They are usually low risk by proposed criteria and appear to behave in an indolent manner, though larger studies are needed to confirm this. Recognition that SFT may present as a superficial mass will avoid misclassification as other CD34-positive neoplasms that frequently arise in the skin and subcutaneous tissue.

Extrapleural solitary fibrous tumor: A distinct entity from pleural solitary fibrous tumor. An update on clinical, molecular and diagnostic features

Solitary fibrous tumor (SFT) is a mesenchymal neoplasm that was originally described to be localized in the pleura, but thereafter, this has been reported in several anatomic sites. Although the etiology of the neoplasm remains largely unknown, the pathogenesis seems to be related to an NAB2-STAT6 fusion gene due to paracentric inversion on chromosome 12q13. The diagnosis of extrapleural SFT is challenging, owing to its rarity, and requires an integrated approach that includes specific clinical, histological, immunohistochemical, and even molecular findings. Histologically, extrapleural SFT shares morphological features same as those of the pleural SFT because it is characterized by a patternless distribution of both oval- and spindle-shaped cells in a variable collagen stroma. In addition, morphological variants of mixoid, fat-forming, and giant cell-rich tumors are described. A correct diagnosis is mandatory for a proper therapy and management of the patients with extrapleural SFT, as extrapleural SFT is usually more aggressive than pleural form, particularly cases occurring in the mediastinum, retroperitoneum, pelvis, and meninges. Although SFT is usually considered as a clinically indolent neoplasm, the prognosis is substantially unpredictable and only partially related to morphological features. In this context, cellularity, neoplastic borders, cellular atypias, and mitotic activity can show a wide range of variability. We review extrapleural SFT by discussing diagnostic clues, differential diagnosis, recent molecular findings, and prognostic factors.

Cutaneous and Superficial Soft Tissue CD34+ Spindle Cell Proliferation

CONTEXT

- Cutaneous and superficial soft tissue spindle cell proliferations with CD34 expression represent a unique heterogeneous group of lesions. They can pose diagnostic challenges for unaware pathologists in their daily practice.

OBJECTIVE

- To review selected entities of CD34⁺ spindle cell proliferations in the skin and superficial soft tissue. The effective diagnostic approaches using clinical, histopathologic, and immunophenotypical findings are discussed within a broad spectrum of differential diagnosis.

DATA SOURCES

- All information used in the article is obtained from published literature by PubMed search and Internet-based search engines. The authors' collective experience and real-life examples are also used.

CONCLUSIONS

- Spindle cell proliferations with CD34 positivity can be worked up to a definitive diagnosis by using clinical, histopathologic, and immunophenotypical findings. Familiarity with these entities helps pathologists make the accurate diagnosis.

Superficial CD34-positive fibroblastic tumour: a clinicopathological and immunohistochemical study of an additional series

AIMS

To describe an additional series of superficial CD34-positive fibroblastic tumour, a newly described neoplasm, in order to enhance the recognition of an emerging novel entity.

METHODS AND RESULTS

The clinicopathological features and immunophenotypes of 11 cases of superficial CD34-positive fibroblastic tumour were studied. There were eight males and three females, with a median age of 36 years. Tumours occurred in the thigh (n = 4), buttock (n = 3), shoulder (n = 2), upper arm (n = 1), and waist (n = 1). Histologically, all tumours were characterized by relative circumscription, pleomorphic spindled to polygonal cells with variably enlarged bizarre-appearing cells, intranuclear cytoplasmic pseudoinclusions, and extremely low mitotic activity. Immunohistochemically, neoplastic cells showed diffuse and strong expression of CD34 and focal staining of cytokeratin. Follow-up thus far has revealed an indolent clinical behaviour.

CONCLUSIONS

Superficial CD34-positive fibroblastic tumour represents a new member of the family of cutaneous CD34-positive spindle-cell tumours. Familiarity with its clinicopathological characteristics is helpful in avoiding confusion with a variety of cutaneous mesenchymal tumours with overlapping features.

Hemangiopericytoma of the Cerebellopontine Angle: A Wolf in Sheep's Clothing

Primary meningeal hemangiopericytoma (HPC) is a rare, aggressive dura based tumor that remarkably mimics a meningioma clinically and radiologically. Its occurrence within the cerebellopontine angle (CPA) is exceptional, and establishing the exact diagnosis is of the utmost importance since total resection remains the cornerstone of treatment. A 42-year-old man presented with a three-month history of progressively worsening vertigo and difficulty in walking. On admission, his neurological examination revealed a right peripheral facial palsy, right abducens palsy and left hemiparesis, suggesting the diagnosis of Millard-Gubler syndrome. Computed tomography and magnetic resonance imaging demonstrated a homogeneously enhancing dura based lesion of the right CPA causing major brain stem compression. There was no widening of the ipsilateral internal auditory canal. A standard retrosigmoid craniotomy was performed to access the right CPA. Exposure of the lesion revealed a well-encapsulated, gray, fibrous lesion, which appeared to originate from the tentorium. Gross total resection was achieved and confirmed radiologically. The microscopic features and the immunohistochemical profile confirmed the diagnosis of a HPC, and adjuvant radiation therapy was administered. Ten years later, the patient presented with a severe neurological deficit due to a local recurrence, but at that time refused any second intervention. He died three months later. HPC can locate within the CPA and present as a Millard-Gubler syndrome. The diagnosis should be kept in mind in case of a CPA dura based tumor. Radical surgery plus radiation therapy can maximize the recurrence-free survival and close follow-up remains mandatory to spot recurrences early.

Possible involvement of inflammatory/reparative processes in the development of uterine fibroids

Uterine leiomyomas are benign tumors in the smooth muscle layer of the uterus. The most common histological type is the "usual leiomyoma", characterized by overexpression of ECM proteins, whereas the "cellular type" has higher cellular content. Our objective is to investigate the involvement of inflammatory and reparative processes in leiomyoma pathobiology. Using a morphological approach, we investigate the presence of inflammatory cells. Next, we determine the localization of the ECM, the presence/absence of fibrotic cells via α-sma and desmin and the immunohistochemical profile of the mesenchymal cells with respect to CD34. Finally, we explore the effect of inflammatory mediators (TNF-α, IL-1β, IL-6, IL-15, GM-CSF and IFN-γ) on pro-fibrotic factor activin A mRNA expression in vitro. Higher numbers of macrophages were found inside and close to leiomyomas as compared to the more distant myometrium. Cellular leiomyomas showed more macrophages and mast cells than the "usual type". Inside the fibroid tissue, we found cells positive for α-sma, but negative for desmin and a large amount of collagen surrounding the nodule, suggestive of myofibroblasts producing ECM. In the myometrium and leiomyomas of the "usual type", we identified numerous CD34+ fibroblasts, which are known to give rise to myofibroblasts upon loss of CD34 expression. In leiomyomas of the "cellular type", stromal fibroblasts were CD34-negative. Finally, we found that TNF-α increased activin A mRNA in myometrial and leiomyoma cells. In conclusion, this study demonstrates the presence of inflammatory cells in uterine leiomyomas, which may contribute to excessive ECM production, tissue remodeling and leiomyoma growth.

Clinicopathologic and immunohistochemical features of five new cases of solitary fibrous tumor of the oral cavity

OBJECTIVE

To describe the clinicopathologic and immunohistochemical features of five cases of oral solitary fibrous tumor.

STUDY DESIGN

Clinical data were collected from charts of two oral pathology laboratories of Latin America. All cases were evaluated by conventional hematoxylin and eosin staining and an extended immunohistochemical panel comprising vimentin, CD34, CD99, bcl-2, HHF-35, smooth muscle actin, calponin, S-100 protein, h-caldesmon, and Ki-67.

RESULTS

The study included 1 male (20%) and 4 female (80%) patients, with a median age of 43 years. The most common affected site was the buccal mucosa (40%). Tumors were characterized by proliferation of spindled and ovoid cells in a variably vascular and collagenized stroma. All tumors were positive for vimentin, CD34, bcl-2, and CD99. Recurrence was not observed after complete surgical enucleation.

CONCLUSIONS

Oral solitary fibrous tumors usually appear as well-delimited submucous nodules with a firm-rubbery consistency and covered by intact mucosa. Immunoreactivity for CD34, bcl-2, and CD-99 is helpful to confirm the diagnosis.

Extrapleural Solitary Fibrous Tumor of the Foot A Case Report

Solitary fibrous tumors are uncommon mesenchymal neoplasms that were initially described as pleural tumors, but in recent years, numerous extrapleural sites have been reported. A solitary fibrous tumor is characterized as a circumscribed, painless mass with a patternless growth pattern, positive CD34 spindle-shaped cells, bcl-2, and dense keloidal collagen with areas of hypercellularity and hypocellularity. This case report describes a 55-year-old male veteran who presented with a rare manifestation of an extrapleural solitary fibrous tumor of the medial right hallux. Microscopic and immunohistochemical findings were consistent with the previously documented characteristics of solitary fibrous tumors. Complete surgical excision of the tumor is the treatment of choice.

Malignant Solitary Fibrous Tumor of the Pancreas

Solitary fibrous tumor (SFT) arising in the pancreas is exceedingly rare, with only 11 cases reported in the English literature. All cases described thus far have exhibited benign histology. We report the first case of malignant SFT of the pancreas. The patient was a 52-year-old woman who presented with obstructive jaundice and a 15-cm pancreatic head mass. The mass showed areas with typical histologic features for SFT including small fibroblastlike cells arranged in the well-characterized "patternless pattern" of architecture, hemangiopericytomalike vessels, areas with dense collagen and infrequent mitoses (0-2 per 10 high-power fields [HPFs]). In addition, multiple areas with an overtly sarcomatous morphology were present, containing large spindle and epithelioid cells with nuclear pleomorphism, marked cellularity, up to17 mitoses per 10 HPFs, and necrosis. Immunohistochemical stains were positive for CD34 and B-cell CLL/lymphoma 2 (Bcl-2) in both benign and malignant components and showed strong, diffuse p53 and p16 staining in the malignant component. At last follow-up (40 months), the patient was alive and well without evidence of disease. However, given that the presence of a malignant component in extrapancreatic SFT has been associated with recurrence/metastasis and death, complete surgical resection and close long-term follow-up is required.

Prognosis of solitary fibrous tumors: a multicenter study

BACKGROUND

Solitary fibrous tumors (SFTs) are rare mesenchymal tumors, and data regarding outcome and prognostic factors are scarce. We report the outcome and analysis of prognostic factors of a retrospective multicenter cohort study for patients treated for SFTs.

METHODS

Retrospective analysis was performed of patients treated for SFTs between 1995 and 2012. Clinical and histopathological features were analyzed for prognostic value. Endpoints were set at local recurrence, metastasis formation, or death. Survival was analyzed using Kaplan-Meier and Cox proportional hazards analyses.

RESULTS

A total of 81 patients underwent surgical resection of a SFT with curative intent. During follow-up, 21 patients developed distant metastases, while 18 patients developed local recurrence. The 5-year overall survival was 84 %. The local recurrence rate and the metastasis rate at 5 years were 29 and 34 %, respectively. Of all factors analyzed, positive resection margin significantly correlated with local recurrence [hazard ratio (HR) 4.8; 95 % confidence interval (95 % CI) 1.5-14.9]. Tumor size >10 cm (HR 4.4; 95 % CI 1.7-11.5) and high mitosis rate (HR 3.3; 95 % CI 1.06-10.3) significantly correlated with higher incidence of metastases. The combination of tumors >10 cm and high mitosis rate significantly correlated with higher incidence of metastases (HR 4.8; 95 % CI 1.4-16.2) and showed a trend toward worse overall survival (HR 5.7; 95 % CI 0.95-34.7).

CONCLUSIONS

A substantial portion of patients with a SFT developed local recurrence or metastases. Local recurrence is significantly higher in patients with positive resection margins; metastasis frequency is significantly higher in patients with tumors >10 cm and tumors with a high mitosis rate.

Extrathoracic location and "borderline" histology are associated with recurrence of solitary fibrous tumors after surgical resection

BACKGROUND

Most solitary fibrous tumors (SFTs) are cured by complete resection, but many recurrent and metastatic SFTs do not respond to treatment and are fatal. Malignant histology, defined by England's pathologic criteria, is strongly associated with recurrence, but some benign SFTs still behave aggressively. Several studies have suggested that extrathoracic SFTs have a worse prognosis. We reviewed thoracic and extrathoracic SFTs from our institution to determine if extrathoracic location is associated with recurrence, independent of malignant histology.

METHODS

With IRB approval, we retrieved patient pathology reports from the Johns Hopkins Surgical Pathology database between 1991 and 2011 and included 83 SFT patients in our analysis. Patient history and outcomes were obtained from the medical record and primary care physicians. Predictors of recurrence were analyzed by univariate and multivariate analysis and survival determined by the Kaplan-Meier method.

RESULTS

Of the 83 patients, 59 had extrathoracic SFTs in neurologic (n = 24), extremity or head/neck (n = 13), or visceral/intraabdominal (n = 22) sites. A total of 74 SFTs were classified benign and 9 as malignant. Of the 14 recurrences, 13 occurred in extrathoracic SFTs; only 7 were classified as malignant. Multivariate analysis confirmed that malignant histology had the strongest association with recurrence, but extrathoracic location also independently predicted recurrence. A total of 20 benign SFTs possessed 1 or more of England's criteria but to an insufficient degree for malignant classification. These "borderline" SFTs were more likely to recur than benign SFTs without these features.

CONCLUSIONS

Extrathoracic and "borderline" SFTs with any of England's criteria have a higher risk of recurrence.

Fibrous and fibrohistiocytic neoplasms: an update

Important advances in fibroblastic and fibrohistiocytic tumors relevant to dermatologists and dermatopathologists include (1) recognition that myxofibrosarcoma is a distinct entity that frequently arises in skin; (2) CD10 is sensitive but not specific atypical fibroxanthoma; (3) neurothekeomas lacking S100 expression are probably fibrohistiocytic/fibroblastic tumors, whereas S100+ myxoid variants are better classified as nerve sheath myxomas; (4) the recognition of a primary cutaneous variant of solitary fibrous tumor; (5) thelimitations of b-catenin immunohistochemistry in desmoid tumors; and (6) the prognostic utility of clinical and histopathologic variables in dermatofibrosarcoma protuberans, and the effects of imatinib mesylate therapy.

Solitary fibrous tumor of the central nervous system: a 15-year literature survey of 220 cases (August 1996-July 2011)

We reviewed the world literature on solitary fibrous tumors of the central nervous system from August 1996 to July 2011, focusing on both clinicopathological features and diagnostic findings. The anatomical distribution of the 220 cases reported so far reveals that most are intracranial and just over one-fifth are intraspinal. In decreasing frequency, intracranial tumors involve the supratentorial and infratentorial compartments, the pontocerebellar angle, the sellar and parasellar regions, and the cranial nerves. Intraspinal tumors are mainly located in the thoracic and cervical segments. Although most solitary fibrous tumors of the central nervous system are dural based, a small subset presents as subpial, intraparenchymal, intraventricular, or as tumors involving the nerve rootlets with no dural connection. Preoperative imaging and intraoperative findings suggest meningioma, schwannoma or neurofibroma, hemangiopericytoma, or pituitary tumors. Immunohistochemistry is critical to establish a definitive histopathological diagnosis. Vimentin, CD34, BCL2, and CD99 are the most consistently positive markers. The usual histologic type generally behaves in a benign manner if complete removal is achieved. Recurrence is anticipated when resection is subtotal or when the tumor exhibits atypical histology. The proliferative index as assessed by MIB1 labeling is of prognostic significance. Occasionally, tumors featuring conventional morphology may recur, perhaps because of minimal residual disease left behind during surgical extirpation. Rare extracranial metastases and tumor-related deaths are on record. Surgery is the treatment of choice. Stereotactic and external beam radiation therapy may be indicated for postsurgical tumor remnants and for unresectable recurrences. Long-term active surveillance of the patients is mandatory.

Solitary Fibrous Tumor of the Vagina

Solitary fibrous tumor, initially described in the pleura, is now known to occur in various extrathoracic sites. However, its occurrence in the female genital tract, especially the vagina, is extremely rare. The authors report here a case of a well-circumscribed vaginal spindle cell nodule in a 48-year-old woman with features consistent with solitary fibrous tumor. The diagnosis was established histologically by the varying pattern with hypocellular fibrous areas alternating with hypercellular areas and hemangiopericytoma-like areas and, immunohistochemically by the strong positive reaction for CD34 and Bcl2 with a negative reaction for all other spindle cell and epithelial markers. The differential diagnosis is discussed and a review of the literature is presented.

Hemangiopericytoma-like dermatofibroma with mast cells

We report an unusual case of hemangiopericytoma-like dermatofibroma in the right shoulder of an 82-year-old patient with a well-defined nodular growth located in the dermis. Microscopic study revealed a band of haphazardly arranged cells with a vascular component of gaping, simple, endothelial-lined vascular structures with intervening postcapillary venules and capillary-sized slit-like "staghorn" vascular channels filled with erythrocytes; abundant mast cells were also observed. The neoplasm cells were positive for CD68 and Factor XIIIA and negative for CD34. Few data have been published on the presence of abundant mast cells (tryptase and CD117 positive) in these neoplasm. The differential diagnosis of this entity should consider other spindle cell neoplasm, including hemangiopericytoma/solitary fibrous tumor, dermatofibrosarcoma protuberans, myopericytoma, angioleiomyoma, amelanotic melanoma, pecoma, and benign and malignant peripheral nerve tumors. We present an infrequent case of dermatofibroma with a vascular pattern resembling hemangiopericytoma and the presence of abundant mast cells, which may be responsible for this vascular component.

Hemangiopericytomas of the skull base

Object

Intracranial hemangiopericytomas are frequently located along the dural sinuses along the skull base and represent rare, aggressive CNS neoplasms that are difficult to distinguish from meningiomas based on both imaging and gross characteristics. The authors of this study describe 3 patients with these lesions and review the pertinent literature.

Methods

Two men and 1 woman, whose median age at the time of the initial presentation was 37 years (range 20–53 years), constitute this series. They underwent multimodal treatment consisting of resection, embolization, radiation therapy, and in 1 case chemotherapy.

Results

Two of the 3 patients treated were alive after a mean follow-up of 93 months (range 4–217 months). One patient died 217 months after the initial diagnosis. The longest tumor progression–free interval after the initial or secondary resection was 43 months (range 4–84 months).

Conclusions

Hemangiopericytomas have been reclassified as mesenchymal nonmeningothelial tumors. They have an inevitable tendency to recur locally and metastasize distally. The mainstay of therapy remains an aggressive attempt to achieve gross-total resection at the initial surgery. Postoperative adjuvant radiotherapy should be offered to all patients, regardless of the degree of resection achieved. Diligent long-term follow-up is paramount as local recurrences and distal metastases can develop sometimes years after the initial treatment.

Predictors of mortality following treatment of intracranial hemangiopericytoma

OBJECT

Intracranial hemangiopericytoma (HPC) is a rare and malignant extraaxial tumor with a high proclivity toward recurrence and metastasis. Given this lesion's rarity, little information exists on prognostic factors influencing mortality rates following treatment with surgery or radiation or both. A systematic review of the published literature was performed to ascertain predictors of death following treatment for intracranial HPC.

METHODS

The authors identified 563 patients with intracranial HPC in the published literature, 277 of whom had information on the duration of follow-up. Statistical analysis of survival was performed using Kaplan-Meier and Cox regression analysis.

RESULTS

Hemangiopericytoma was diagnosed in 246 males and 204 females, ranging in age from 1 month to 80 years. Among patients treated for HPC, overall median survival was 13 years, with 1-, 5-, 10-, and 20-year survival rates of 95%, 82%, 60%, and 23%, respectively. Gross-total resection alone (105 patients) was associated with superior survival rates overall, with a median survival of 13 years, whereas subtotal resection alone (23 patients) resulted in a median survival of 9.75 years. Subtotal resection plus adjuvant radiotherapy led to a median survival of 6 years. Gross-total resection was associated with a superior survival benefit to patients regardless of the addition or absence of radiation, and patients receiving > 50 Gy of radiation had worse survival outcomes (median survival 4 vs 18.6 years, p < 0.01, log-rank test). Patients with tumors of the posterior fossa had a median survival of 10.75 versus 15.6 years for those with non-posterior fossa tumors (p < 0.05, log-rank test).

CONCLUSIONS

Treatment with gross-total resection provides the greatest survival advantage and should be pursued aggressively as an initial therapy. The addition of postoperative adjuvant radiation does not seem to confer a survival benefit.

Update on immunohistochemical methods relevant to dermatopathology

CONTEXT

Dermatopathology covers a large variety of entities, some having very similar histologic appearances. Immunohistochemistry is an incredibly helpful tool that is useful in diagnosis as well as prognosis of selected skin tumors.

OBJECTIVE

To provide a comprehensive review of recent trends and immunohistochemical stains used by dermatopathologists. Emphasis is placed on new stains as well as novel uses of existing stains.

DATA SOURCES

All data were gathered from published journal articles available through the National Center for Biotechnology Information PubMed database.

CONCLUSIONS

New immunohistochemical targets are continually being found, contributing to more accurate diagnosis and classification of skin tumors. The presence of specific markers can be used to determine the aggressiveness of malignancies and design treatment strategies. In addition, application of existing stains can help determine intravascular spread of malignancy in primary cutaneous lesions. And use of rapid immunohistochemical staining techniques on frozen sections can assist in more complete excision of tumor margins. Immunohistochemistry is a highly versatile and growing tool of dermatopathologists.

Extrapleural solitary fibrous tumor: a clinicopathologic study of 19 cases

This study reports a series of 19 extrapleural solitary fibrous tumors. The patients included 6 men and 13 women with age ranging from 27 to 86 years. Three patients showed local recurrence. In 2 tumors, a diagnosis of malignancy was made. All of the tumors were strongly positive for CD34, and 3 of them expressed high levels of progesterone receptor. Solitary fibrous tumors are fairly rare, occurring in many parts of the body, and their behavior is unpredictable.

CD34-reactive tumors of the skin. An updated review of an ever-growing list of lesions

Over the past few years, a growing number of cutaneous tumors expressing CD34 is being reported. The list contains benign and malignant neoplasms as well as reactive and hamartomatous lesions of diverse lineages of differentiation, including fibroblastic, myofibroblastic, fibrohistiocytic, vascular, neural, adipocytic, smooth muscle, hematopoietic, melanocytic and epithelial. The more frequent diagnostic difficulties are found in spindle cell proliferations, mainly in those of the fibrocytic lineage. In part, this is because of the fact that in this area are, aside to well-defined entities, histologically and clinically diverse, recently reported cutaneous CD34-reactive lesions, whose definitions, limits and relationships are not completely established. The CD34 expression plays a key role in the differential diagnosis of some tumors, such as dermatofibrosarcoma protuberans, epithelioid sarcoma or pleomorphic hyalinizing angiectatic tumor of soft parts, with important therapeutic consequences. In others, as in desmoplastic trichilemmoma, it can help to resolve diagnostic problems in concrete cases. Finally, in many of the CD34-positive lesions, the diagnosis with the hematoxylin and eosin stain is straightforward. However, in all of them, the knowledge of the immunohistochemical profile contributes to our understanding of the cutaneous pathology.

Hemangiopericytoma of the cerebellopontine angle: a case report and review of the literature

BACKGROUND

Intracranial hemangiopericytoma represents a rare intracranial tumor that is typically difficult to distinguish from meningioma based on clinical presentation and radiographic findings. These inherently aggressive neoplasms have been observed to occur in numerous intracranial compartments; however, isolated involvement of the CPA is essentially unreported. The authors present a case of a young lady with presumed right acoustic schwannoma, which proved to be HPC on histopathology. The case is described; and a review of the literature pertaining to the diagnosis, optimal management, and follow-up for these lesions is provided.

CASE DESCRIPTION

A 37-year-old Asian woman presented with a 7-month history of right ear and mandible numbness, as well as subjective hearing loss involving the right ear. Magnetic resonance imaging demonstrated the presence of a homogeneously enhancing extraaxial lesion in the right CPA, radiographically suggestive of an acoustic schwannoma. The lesion proved to be an intracranial HPC on histologic sections. Review of the neurosurgical literature yielded only one prior detailed account of HPC confined to the CPA. The patient underwent right retrosigmoid craniotomy for gross total resection of the mass, followed by stereotactic radiotherapy several weeks postoperatively.

CONCLUSION

Given the fundamentally different treatment approach for HPCs over other more common CPA tumors, it is imperative that the treating surgeon consider this rare diagnosis when evaluating patients with lesions localized to this area. Specifically, gross total resection, followed by adjuvant SRT, provides patients with the highest probability for disease-free survival, based on current evidence in the neurosurgical literature.