Update on hemangiomas and vascular malformations

Antiangiogenic role of natural flavonoids and their molecular mechanism: an update

Background

Angiogenesis is the development of new blood vessels from the existing vasculature, which is important in normal developmental processes. Angiogenesis is a key step in tumor growth, invasion, and metastasis. Angiogenesis is necessary for the proper nourishment and removal of metabolic wastes from tumor sites. Therefore, modulation of angiogenesis is considered a therapeutic strategy of great importance for human health.

Main body

Numerous bioactive plant compounds are recently tested for their antiangiogenic potential. Among the most frequently studied are flavonoids which are abundantly present in fruits and vegetables. Flavonoids inhibit angiogenesis and metastasis through the regulation of multiple signaling pathways. Flavonoids regulate the expression of VEGF, matrix metalloproteinases (MMPs), EGFR, and inhibit NFB, PI3-K/Akt, and ERK1/2 signaling pathways, thereby causing strong antiangiogenic effects. This present review aimed to provide up-to-date information on the molecular mechanisms of antiangiogenic properties of natural flavonoids.

Conclusion

Presently developed antiangiogenic drugs in malignant growth treatment do not meet assumptions about adequacy and safety. So further investigations are needed in this field in the future. More recently, flavonoids are the most effective antiangiogenic agent, by inhibition of signaling pathways.

Cutaneous vascular lesions in the pediatric population: a review of laser surgery applications and lesion-specific device parameters

Laser surgery is becoming an increasingly efficacious and customizable treatment modality for the management of pediatric vascular lesions. Proper use requires a thorough understanding of the scientific principles of laser surgery and knowledge of the various lasers available. Moreover, each laser has a multitude of settings that can be employed to properly target the lesion at hand. Each patient will present with unique challenges and variations in the presentation of their vascular lesion. This requires understanding of the most effective laser to use for each lesion and the factors that may alter the desired device settings. Using key search terms, a literature search was conducted on laser surgery for pediatric vascular lesions using PubMed/MEDLINE and Embase for articles published in English or French. Ultimately, 52 articles met our search criteria. The laser indications, limitations, and settings utilized for each type of vascular lesion were compiled for the purposes of this summative review. Laser surgery is an effective and appropriate option for the treatment of certain pediatric vascular lesions. Knowledge of optimal device parameters in every setting is essential to good clinical practice.

Current Therapeutic Options in Sturge-Weber Syndrome

Sturge-Weber syndrome is a vascular malformation syndrome consisting of a facial port-wine birthmark associated with malformed leptomeningeal blood vessels and a choroid "angioma" of the eye. It is a rare neurocutaneous disorder that occurs sporadically, is not inherited, and is caused by a somatic mosaic mutation in GNAQ. In patients with Sturge-Weber syndrome, brain involvement typically presents in infancy with seizures, strokes, and stroke-like episodes, and a range of neurologic impairments. Standard treatment includes laser therapy for the birthmark, control of glaucoma through eyedrops or surgery, and the use of anticonvulsants. Increasingly low-dose aspirin is offered. Treatment with propranolol has been tried generally without the dramatic results seen in hemangiomas. Treatment with an anticonvulsant or low-dose aspirin or both before the onset of seizures is an option. Surgical resection may be offered to those whose seizures are medically refractory. Endocrine, medical rehabilitation and cognitive comorbidities are important to manage. In the future, new therapeutic options are likely to be offered stemming from preclinical studies and small pilot clinical trials currently ongoing. Discovery of the causative somatic mosaic mutation suggests new insights into the pathophysiology of this vascular malformation disorder, and potential novel treatment strategies for future study. The mutation results in constitutive overactivation of the Ras-Raf-MEK-ERK and the HIPPO-YAP pathways and inhibitors of these pathways may in the future prove useful in the treatment of Sturge-Weber syndrome.

Benign osseous and articular abnormalities of the pelvis: a review of CT imaging findings

Computed tomography (CT) has become the standard of care for evaluation and follow-up for a wide range of abdominal and pelvic pathology. Many incidental osseous and articular abnormalities of the pelvis are detected on these studies, most of which have a benign etiology. However, most of these studies are interpreted by nonmusculoskeletal radiologists, who may not be familiar with the CT appearances of these benign musculoskeletal abnormalities. Uncertainty often leads to mischaracterization or unnecessary follow-up, resulting in increased health care costs and patient anxiety. This article reviews the CT appearance of the benign musculoskeletal entities that occur in pelvis.

[Sturge-Weber syndrome]

Sturge-Weber syndrome (SWS) is a rare congenital disease which affects the brain, the skin and the eyes. It is a sporadically occurring neurocutaneous syndrome affecting the intracerebral veins (venous angiomatosis). The frequency is estimated to be 1 in 50,000 births [1]. The main symptom is intracranial leptomeningeal angiomatosis which mostly affects the occipital and posterior parietal lobes and can occur unilaterally and also bilaterally. Facial cutaneous vascular alterations occur ipsilaterally in the form of port wine stains (nevus flammeus) which are normally found in the catchment area of the trigeminal branch VI. Other clinical symptoms associated with SWS are seizures, glaucoma, headaches, transient neurological stroke-like episodes and cognitive impairment. Neurological cortical symptoms often include hemiparesis, hemiatrophy and hemianopsia.

Psychologic consequences of facial dermatoses

The attractiveness of the human body has always been an important issue in the fields of sociology, psychology, and psychiatry and also in the field of dermatology. In psychodermatology, one often discovers how all these fields intermingle to produce elaborate situations and extreme human difficulties. Perfect skin is widely adored in literature, poetry, and biblical texts, as well as in advertisements, movies, and television. Because in most societies the face is the body part that is visible, imperfections of the skin are also visible; therefore, its flawed appearance bears the potential to become a source of misery to some.

Nonselective β-blocker propranolol for orbital and periorbital hemangiomas in infants: a new first-line of treatment?

Purpose

To determine the effectiveness and possible side effects of using propranolol for the treatment of orbital and periorbital infantile hemangiomas.

Methods

Infants with periorbital or orbital hemangiomas who had not received either local or systemic corticosteroids were recruited. The changes in tumor size, color, and texture, and any side effects of the drug were recorded.

Results

Fifteen infants with a mean age of 8.13 ± 4.7 months were treated according to the set protocol. A change in the color and texture of the hemangioma occurred in the first week following treatment. Mean duration of treatment was 7.67 ± 3.96 months. The size of hemangiomas decreased from a mean of 2.4 ± 0.9 cm to a mean of 1.6 ± 1.0 cm 3 months after treatment (P = 0.001). One patient had to stop the drug because of peripheral vascular ischemia. Another case had the dose reduced to control a mild hyperglycemia. Serious side effects were not observed. A single case of tumor regrowth (8.3%) was recorded.

Conclusion

Treatment of 1–2 mg/kg/day propranolol proved to be effective and associated with minimal side effects. It is likely to replace steroids as the first-line of treatment of hemangiomas in infants.

Subtotal splenic embolization is a safe and effective treatment for isolated splenic vascular tumors associated with consumptive coagulopathy

Consumptive coagulopathy is a known complication of large vascular tumors. We describe 2 episodes of consumptive coagulopathy in young children, which were secondary to isolated splenic vascular tumors. One child was successfully treated by subtotal embolization of the spleen, whereas the second child required splenectomy after an initial embolization improved--but did not fully control--his consumptive coagulopathy.

Angiogenic targets for potential disorders

This review shall familiarize the readers with various fundamental aspects of angiogenesis. Angiogenesis is a feature of a limited number of physiological processes like wound healing, ovulation, development of the corpus luteum, embryogenesis, lactating breast, during immune response, and during Inflammation. It is driven by a cocktail of growth factors and pro-angiogenic cytokines and is tempered by an equally diverse group of inhibitors of neovascularization. The properties and biological functions of angiogenic growth factors such as VEGF, FGF-2, nitric oxide, MMP, angiopoietin, TGF-β as well as various inhibitors such as angiostatin, endostatin, thrombospondin, canstatin, DII4, PEDF are discussed in this review with respect to their impact on angiogenic process. In recent years, it has become increasingly evident that excessive, insufficient, or abnormal angiogenesis contributes to the pathogenesis of many more disorders. A long list of disorders is characterized or caused by excessive or insufficient angiogenesis whereas several congenital or inherited diseases are also caused by abnormal vascular remodeling. It may be possible in the future to develop specific anti-angiogenic agents that offer a potential therapy for cancer and angiogenic diseases.

Transarterial embolization of a scalp hemangioma presenting with Kasabach-Merritt syndrome

A 2-month-old infant presented with an enlarging scalp hemangioma and consumptive coagulopathy. The patient became severely thrombocytopenic despite medical treatment. Transarterial embolization with Onyx was performed with significant reduction in the size of the tumor and complete resolution of the thrombocytopenia within 12 hours. Onyx embolization appears to be an excellent treatment option for hemangiomas presenting with Kasabach-Merritt syndrome that are unresponsive to standard medical therapy.

Kaposiform hemangioendothelioma

Kaposiform hemangioendothelioma (KHE) is a rare, locally aggressive vascular neoplasm that mainly occurs during childhood. It generally originates on the skin, usually affecting deeper tissue by infiltrative growth. It appears as one or multiple masses, and in most cases is associated to consumptive coagulopathy (Kasabach-Merritt syndrome), and lymphangiomatosis. Although visceral involvement is very uncommon, several cases with bone, retroperitoneal, or mediastinal involvement have been described. These tumors tend to be locally invasive, but are not known to produce distant metastases. The development of KHE in adolescents or in adults is very rare, but cases have also been described. Several factors are associated with the outcome of patients with KHE: accessibility to surgical excision, location (cutaneous versus visceral), size of tumoral mass, clinical response to interferon and glucocorticoids, and the absence of lymphangiomatosis and Kasabach-Merritt syndrome, may result in partial remissions. On the other hand, bulk visceral masses lead to a 40-50% mortality rate, mainly due to progressive failure of the infiltrated organ(s), in spite of interferon, glucocorticoids, and combined chemotherapy. In conclusion, the onset of a consumptive coagulopathy following the presence of a vascular tumor, in children as well as in older patients, should spark suspicion of KHE, among other entities.

Group A streptococcal infection of an intramuscular venous malformation: a case report and review of the literature

Intramuscular venous malformations are uncommon benign masses of vascular origin that can occur anywhere in the body. They can be small and clinically insignificant or can be large and violate tissue planes and viscera. Presentation is as variable as the extent of the lesions. They can be diagnosed as a result of local pain and swelling or as incidental findings. Rarely, venous malformations can get infected and present with fever or other more severe systemic symptoms. The literature is sparse regarding infection of intramuscular venous malformations. This case describes the presentation, diagnosis, and management of a patient with group A streptococcal infection of a previously undiagnosed intramuscularvenous malformation in a patient who presented to our pediatric emergency department.

[Vascular malformation of the head and neck--diagnosis and treatment]

Vascular malformations are the most common anomalies appearing from birth to any adulthood. They are not clinically and morphologically homogenous group. They may occur at different place but most often in the subcutaneous or submucous space in the oral cavity, pharynx, the paranasal sinuses and nose. The aim of this study was to present the difficulties in diagnosis and treatment of head and neck vascular malformations in patients hospitalized in ENT Department University of Lodz from 2001 to 2006. From 17 patients with vascular malformations we choose four to careful evaluation. Two patients had neck vascular malformation, two had the paranasal and nose sinuses tumors. Presented lesions were categorized as "low-flow" vascular malformation. In two cases there was vascular and lymphatic malformation, deeply located in the neck. In two cases arisen in the nose and the paranasal sinuses, there were capillary and cavernous types. We pointed out the clinical signs and diagnostic problems in deep vascular tumors and bleeding risk concerning treatment procedure. Even a needle biopsy and radiological imagining did not confirm the preoperative diagnosis. CT and MRI is recommended to delineate the extend the lesion, and evaluation of its special anatomical location, surrounding arteries, vessels and important neck structure prior to surgery. In the paranasal and nose tumor CT could show bone destructions as well.

CONCLUSIONS

Surgical careful excision has been favorable in depth neck laying and extended paranasal and nose vascular malformation. Because of the risk of bleeding careful hemostasis are important challenges in the surgical removal, so embolization is preferred in some cases.

Angioblastoma showing aggravation after treatment with long-pulsed Nd:YAG laser (1064 nm)

Angioblastoma usually develops in infancy or early childhood on the neck or upper trunk. It is known to be slowly progressive and benign in nature, but treatment guidelines have not yet been established. Spontaneous regression has been occasionally documented, and treatment with pulsed dye laser, excision, high-dose steroids, and interferon alpha have been successful in individual patients. Our patient experienced partial response to interferon alpha injection, and for further treatment, long-pulsed Nd:YAG laser (1064 nm) treatment was performed. However, unexpectedly, the tumor was rapidly aggravated. We report this occurrence to increase awareness of trauma-induced aggravation phenomena in angioblastoma.

Congenital ulcerating hemangioma in a baby with KRAS mutation and cardio-facio-cutaneous syndrome

CFC syndrome is a genetically heterogenous condition. Missense mutations have been identified in BRAF, KRAS, MEK1 and MEK2. We have reported here a KRAS mutation in a baby girl with an early clinical diagnosis of CFC syndrome associated with a large ulcerating hemangioma. Although ectodermal abnormalities have been described in all individuals with this condition, features such as ichthyosis and hemangioma have been previously found only in those patients carrying a mutation in BRAF, and not in KRAS. The findings we have described contrast with these observations. The relatively high frequency of hemangiomas in CFC syndrome suggests that defects in the expression of the MAPK pathway may alter endothelial cell proliferation. Increased understanding of how the molecular pathways with which defects in CFC syndrome predispose affected individuals to hemangiomas might offer insights into the pathogenesis of this common childhood tumour in the general population.

Acquired port-wine stain in a pediatric patient

BACKGROUND

Acquired port-wine stains (PWSs) are vascular lesions that are identical to congenital PWSs morphologically and histopathologically.

OBJECTIVE

Because acquired PWSs are rarely seen in adult and pediatric patients, we present a 9-year-old boy with an acquired PWS on his left forearm.

CONCLUSION

None of the proposed etiologies, such as trauma, chronic sun exposure, or hormonal medication, was applicable to our patient, and a literature review showed us that acquired PWSs give a faster and better response to pulsed dye laser therapy than congenital lesions do.

Kaposiform hemangioendothelioma arising in the ethmoid sinus of an 8-year-old girl with severe epistaxis

BACKGROUND

Epistaxis is very common during childhood. It occurs primarily in boys and is usually self-limiting. Trauma and nose picking are among the most common causes. In general, epistaxis can be easily treated with anterior nasal packing or electrocoagulation.

METHODS

We report a case of an 8-year-old girl with severe unilateral epistaxis.

RESULTS

The bleeding originated from a kaposiform hemangioendothelioma arising in the left nasal cavity and ethmoid sinus. The feeding vessels originating from the maxillary artery were first embolized. The tumor was then surgically removed through a combined external ethmoidectomy and endonasal approach. The postoperative course was uneventful. MRI at 6 months after surgery showed no tumor recurrence.

CONCLUSIONS

We report a previously undescribed cause of epistaxis in children, namely, a kaposiform hemangioendothelioma. To our knowledge, this is the first such case in the English-language literature. The differential diagnosis of severe unilateral nasal bleeding among the pediatric population should include the possibility of a kaposiform hemangioendothelioma.

Usefulness of D2-40 immunohistochemistry for differentiation between kaposiform hemangioendothelioma and tufted angioma

BACKGROUND

Recent investigations have demonstrated the utility of the monoclonal antibody D2-40 as a marker for lymphatic endothelium. D2-40 can be used on formalin-fixed and paraffin-embedded materials. Our objective was to elucidate, using D2-40 immunohistochemistry, the differences among capillary hemangiomas, and especially between kaposiform hemangioendothelioma (KHE) and tufted angioma (TA). We studied four cases of KHE, nine cases of TA, and 31 cases of other vascular tumors. Antibodies against CD31, CD34, factor VIII-related antigen, and GLUT1 were also applied.

RESULTS

In KHE, D2-40 was markedly reactive for three and partially for one of four cases in the peripheral area of Kaposi's sarcoma-like proliferative capillaries and negative in the surrounding dilated vessels. In TA, D2-40 was partially positive in the surrounding dilated vessels and negative in cannonball-like proliferative capillaries.

CONCLUSIONS

Our results suggest that D2-40 is a useful antibody for immunohistochemical discrimination between KHE and TA. In addition, the difference of immunostaining pattern of D2-40 is limited to the peripheral area of capillary proliferation and surrounding dilated vessels; therefore, it is suggested that KHE and TA may reflect different stages in the evolution of a single entity. Namely, they may originate from stem cells possessing the characteristics of both lymphatic and blood vessel endothelial lineages.

Anti-angiogenic and anti-tumor activities of 2'-hydroxy-4'-methoxychalcone

In the present study, we evaluated the in vitro and in vivo anti-angiogenic and anti-tumor activities of 2'-hydroxy-4'-methoxychalcone (HMC). HMC decreased angiogenesis in both chick embryos in the chorioallantoic membrane assay and basic fibroblast growth factor (bFGF)-induced vessel formation in the mouse Matrigel plug assay. This compound also reduced the proliferation of calf pulmonary arterial endothelial cells and was found to possess relatively weak gelatinase/collagenase inhibitory activity in vitro. HMC, when administered subcutaneously at the dose of 30 mg/kg for 20 d to mice implanted with murine Lewis lung carcinoma, caused a significant inhibition of tumor volume by 27.2%. Intraperitoneal (i.p.) treatment at the same dosage for 10 d to ICR mice bearing sarcoma 180 caused a significant suppression in tumor weight by 33.7%. Taken together, out data demonstrate that the anti-angiogenic activities of HMC might be due to anti-proliferative activity under inhibition of the induction of COX-2 enzyme. Furthermore, the results suggest that the potent anti-angiogenic activity of HMC seems to be the possible mechanism of action in these animal models of solid tumors.

[New prognostic and predictive factors in advanced colorectal cancer]

Cancer patients often show a clinical tendency to thromboembolic events. This tendency is due to tumor cell-related factors together with the damage of the vascular endothelial exerted by chemotherapy treatment. Gastrointestinal tumors especially contribute to these types of events. More recently, the implication of tumor angiogenesis in clotting/fibrynolisys and plasminogen systems activation has been addressed in cancer patients. Finally, some hemostasis and angiogenesis-related factors such as platelets, von Willebrand factor, fibrinogen, plasminogen activator inhibitor type-1, D dimer, and vascular endotelial growth factor have been highlighted as new potential response and survival predictors in colorectal cancer patients. In this review article, the current evidence supporting the use of these proteins in assessing prognosis in colorectal cancer patients is critically exposed and discussed.

Histopathological reporting of paediatric cutaneous vascular anomalies in relation to proposed multidisciplinary classification system

BACKGROUND

The terminology applied to vascular anomalies has been variable in previously published literature making interpretation suboptimal. The International Society for the Study of Vascular Anomalies (ISSVA) has proposed a revised classification based on clinical features and histopathological findings. This classification is increasingly being accepted as clinically useful and a platform for future studies.

AIMS

To examine the extent to which the ISSVA classification can be practically applied to diagnostic histopathological specimens.

METHODS

Cutaneous vascular lesions received in a single paediatric pathology unit during a 2-year period (2004-5) were reviewed, including glucose transporter protein 1 (GLUT1) immunostaining where required, and lesions were reclassified according to the ISSVA classification.

RESULTS

144 specimens were identified. Appropriate full clinical information was provided in only 17% of cases at submission. Infantile haemangiomas comprised 46% of cases, 18% of which were regressive type, initially inaccurately identified as vascular malformations before GLUT1 immunostaining. 30% of lymphatic malformations and all lymphovenous malformations were previously classified as vascular malformations, not otherwise specified.

CONCLUSIONS

The ISSVA classification of vascular anomalies provides a useful framework for histopathologists to classify vascular anomalies. However, meaningful and appropriate use of such a system is dependent on the adequacy of clinical information provided and routine use of immunohistochemical markers.

Intraosseous haemangioma of the ilium

Intraosseous haemangioma, an uncommon benign vascular tumour, is most commonly seen in adults and tends to involve the vertebrae and the skull. Lesions of flat bones are rare and the imaging findings in these patients are non-specific. We report a unique case of intraosseous haemangioma in the ilium of a 7-year-old girl studied by US, radiography, scintigraphy, CT and MRI.

The potential efficacy of ω-3 fatty acids as anti-angiogenic agents in benign vascular tumors of infancy

Hemangiomas of infancy are benign vascular tumors frequently encountered in pediatrics. Medical treatment (corticosteroids, interferon, chemotherapy, embolization and radiation) in high-risk hemangioma cases could greatly benefit from the addition of new and safer therapies. The rapid growth of hemangiomas during the proliferative phase occurs secondary to a process of local uncontrolled angiogenesis, involving potent mediators such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). We hypothesize that omega-3 fatty acids, naturally occurring nutrients of proven health benefit to infants, could become an alternative or an adjuvant treatment for hemangiomas, by slowing down their rapid proliferation phase through anti-angiogenic and anti-tumoral effects. Suggested mechanisms of action of omega-3 fatty acids include the downregulation of VEGF and bFGF, and the suppression of pro-angiogenic eicosanoids such as cylooxygenase-2. In this article, we review recent animal and human studies using dietary omega-3 fatty acids supplements, alone or in conjunction with chemotherapy, for the treatment of a variety of tumors dependent on angiogenesis for growth. Available murine hemangioma models offer the opportunity to determine optimal omega-3 fatty acid dose, while taking in account related immunohistochemical markers, clinical outcome and secondary effects, before planning clinical trials. Lessons learned in hemangiomas of infancy may have a broad impact in understanding the phenomenon of dysregulated angiogenesis in cancer research.

Discovery and validation of drug targets for tumour angiogenesis

The formation of blood vessels is a key process in the progression of solid tumours, providing the means for tumour growth and metastasis. A number of drugs are currently being developed to exploit inhibition of angiogenesis in the therapy of cancer. An even greater number of genes that are regulated in models of in vitro angiogenesis have been identified. These genes present potential drug targets for the development of novel, more efficient, drugs that will enable the judicious design of drug cocktails that may be able to account for the many different cancer pathologies and their drug resistance properties. Dealing with the validation of hundreds of potential angiogenesis drug targets requires the utilisation of experimental technology platforms that enable concomitant and dynamic target selection filtering and validation. Such platforms should act as a funnel-like medium-to-low throughput processes that enable the sequential short-listing of hundreds of candidates culminating in the selection of only a small number of well-validated targets that are manageable by drug screening regimes.

Pediatric vascular lesions

The seminal work of Mulliken and Glowacki in 1982 elucidated the histological differences between hemangiomas and vascular malformations: the former are characterized by endothelial cell proliferation, whereas the latter contain mature endothelial cells. Hemangiomas proliferate and then involute, whereas malformations remain stable in size, growing proportionally with the child. Vascular malformations are classified by the predominant vessel type within the lesion (capillary, venous, arterial, and lymphatic). Histological classification therefore correlates with clinical behavior. Treatment of hemangiomas is generally conservative; however, intervention may be required as a result of cosmetically concerning, function-threatening (e.g., interference with eyesight), or life-threatening (e.g., airway obstruction) lesions. Options include steroid therapy, laser treatment, and/or surgical excision. Vascular malformations do not involute and are more likely to require treatment. Treatment options include embolization and surgical resection. Understanding the clinical course of pediatric vascular lesions allows the surgeon to find an appropriate balance between watchful observation, providing reassurance when appropriate, and intervention when needed.

Endothelial cell tumors

Historically, there has been much debate on the nature of infantile hemangiomas as either congenital malformations or benign neoplasms. Some vascular lesions that are present at birth and evidence no proliferative growth are considered to be congenital malformations; other post-natal vascular tumors pursue aggressive and possibly lethal clinical courses. The literature of the last two decades has been reviewed with a hope of clarifying the pathogenesis and underlying molecular lesions of this diverse set of lesions. Genetic investigations of two diseases associated with vascular tumors and abnormalities, von Hippel-Lindau disease, and Hereditary Hemorrhagic Telangiectasia have greatly added to our knowledge of vascular proliferation and provided a tantalizing clue to the pathogenesis of hemangioblastomas. Mutations have also been described in infantile hemangiomas. All of the entities considered, vascular neoplasms as well as malformations, have been examined for the expression of vascular growth factors, their receptors, and factors that appear to promote cell proliferation. Similarly, factors that either block or promote apoptosis have also been examined in various vascular lesions. These studies have in large confirmed our expectations about proliferating tumors that show upregulation of growth promoting factors and inhibition of those that promote apoptosis. In conclusion, although much has been learned about vascular physiology and the control of endothelial proliferation, and while understanding about the molecular pathogenesis of the two inherited diseases mentioned above is detailed but not yet complete, understanding of the pathogenesis of benign and malignant endothelial tumors remains vague.

Intramedullary spindle cell hemangioendothelioma of the thoracic spinal cord--case report

A 28-year-old Malay man presented with progressive paraparesis over a period of 6 months. Magnetic resonance imaging of the spine revealed a thoracic intramedullary spinal cord tumor at the T-7 level with homogeneous enhancement following intravenous gadolinium administration. Laminectomy and partial decompression of the tumor was performed. Histological examination of the tumor revealed features of spindle cell hemangioendothelioma. The patient was managed with limited field radiotherapy followed by systemic interferon therapy. Good neurological improvement was seen subsequently. The patient has survived 48 months with growth restraint at the primary site, although residual neurological deficit persists. Immunotherapy should be considered as a treatment modality for intramedullary hemangioendothelioma of the spinal cord after surgery and radiotherapy.

Angiogenesis and antiangiogenic approaches to sarcomas

Established chemotherapy regimens for advanced or metastatic sarcoma generally have low response rates and substantial toxicity, and resistance often arises quickly, making sarcoma an ideal target for alternative treatment approaches. Antiangiogenic therapies have a number of potential advantages including decreased resistance, fewer side effects, and a broad spectrum of activity. This paper reviews the evidence supporting the use of antiangiogenic therapies for adult soft tissue sarcomas. Human sarcomas express a number of proangiogenic factors that may represent therapeutic targets, with vascular endothelial growth factor being the best characterized, and inhibitors of angiogenesis have antitumor activity in animal models of human sarcomas. Clinical trials are in early stages, although promising results have already been seen. In the future, improved drugs, refined molecular profiling of tumors, and new ways of combining antiangiogenic agents with cytotoxic agents may lead to more effective and tolerable therapies for sarcomas.

Angiogenesis: regulators and clinical applications

Angiogenesis is a fundamental process in reproduction and wound healing. Under these conditions, neovascularization is tightly regulated. Unregulated angiogenesis may lead to several angiogenic diseases and is thought to be indispensable for solid tumor growth and metastasis. The construction of a vascular network requires different sequential steps including the release of proteases from "activated" endothelial cells with subsequent degradation of the basement membrane surrounding the existing vessel, migration of endothelial cells into the interstitial space, endothelial cell proliferation, and differentiation into mature blood vessels. These processes are mediated by a wide range of angiogenic inducers, including growth factors, chemokines, angiogenic enzymes, endothelial specific receptors, and adhesion molecules. Finally, when sufficient neovascularization has occurred, angiogenic factors are down-regulated or the local concentration of inhibitors increases. As a result, the endothelial cells become quiescent, and the vessels remain or regress if no longer needed. Thus, angiogenesis requires many interactions that must be tightly regulated in a spatial and temporal manner. Each of these processes presents possible targets for therapeutic intervention. Synthetic inhibitors of cell invasion (marimastat, Neovastat, AG-3340), adhesion (Vitaxin), or proliferation (TNP-470, thalidomide, Combretastatin A-4), or compounds that interfere with angiogenic growth factors (interferon-alpha, suramin, and analogues) or their receptors (SU6668, SU5416), as well as endogenous inhibitors of angiogenesis (endostatin, interleukin-12) are being evaluated in clinical trials against a variety of solid tumors. As basic knowledge about the control of angiogenesis and its role in tumor growth and metastasis increases, it may be possible in the future to develop specific anti-angiogenic agents that offer a potential therapy for cancer and angiogenic diseases.