Primary cerebral angiosarcoma. Case report

Clinical characteristics and surgical outcomes of primary intracranial angiosarcomas

OBJECTIVE

Primary intracranial angiosarcomas (PIAs) are exceedingly uncommon, with the literature predominantly comprising case reports. The clinical characteristics and prognosis of this condition remain elusive. Our objective is to describe the clinical characteristics and surgical prognosis of this rare disease while offering insights into the most effective contemporary treatment strategy.

METHODS

The authors of this article incorporated a cohort of 28 cases of PIAs, consisting of 3 from our institution and 25 from previously documented literature sources. Subsequently, we conducted both Cox univariate and multivariate analyses to assess the potential risk factors influencing overall survival (OS).

RESULTS

The cohort include 19 males and 9 females with a mean age of 39.6 ± 23.5 years (range: 0.03-73 years). Radiologically, 24 cases were located at supratentorial area, while only 4 cases were located at infratentorial area. 17 cases underwent gross total resection (GTR), and 11 cases underwent Non-GTR. Postoperative radiotherapy was administered to 17 cases, and postoperative chemotherapy was administered to 6 cases. After a mean follow-up time of 21.5 ± 26.4 months, 19 (67.9%) patients died. The 1-year, 2-year, 5-year OS is 55.3%, 50.7% and 24.6%, respectively. Univariate and multivariate Cox regression analysis showed that Non-GTR was the sole factor predicting a shorter OS (p = 0.004).

CONCLUSION

In this study, we found that PIAs have a higher incidence in males than in females, and most cases show evidence of old hemorrhage on preoperative MRI. Through our statistical analysis, GTR plays a crucial role in for treating this rare disease. Further clinical data are needed to validate our conclusions.

Primary central nervous system angiosarcoma with recurrent acute subdural hematoma

Angiosarcoma is an infrequent tumor among sarcomas, especially presenting as a primary tumor within the central nervous system, which can lead to a rapid neurological deterioration and death in few months. We present a 41-year old man with a right frontal enhancing hemorrhagic lesion. Surgery was performed with histopathological findings suggesting a primary central nervous system angiosarcoma. He was discharged uneventfully and received adjuvant chemotherapy and radiotherapy. At 5 months, the follow-up MRI showed two lesions with an acute subdural hematoma, suggesting a relapse. Surgery was again conducted finding tumoral membranes attached to the internal layer of the duramater around the right hemisphere. The patient died a few days later due to the recurrence of the subdural hematoma. This case report illustrates a rare and lethal complication of an unusual tumor. The literature reviewed shows that gross-total resection with adjuvant radiotherapy seems to be the best treatment of choice.

Primary central nervous system angiosarcoma with recurrent acute subdural hematoma

Angiosarcoma is an infrequent tumor among sarcomas, especially presenting as a primary tumor within the central nervous system, which can lead to a rapid neurological deterioration and death in few months. We present a 41-year old man with a right frontal enhancing hemorrhagic lesion. Surgery was performed with histopathological findings suggesting a primary central nervous system angiosarcoma. He was discharged uneventfully and received adjuvant chemotherapy and radiotherapy. At 5 months, the follow-up MRI showed two lesions with an acute subdural hematoma, suggesting a relapse. Surgery was again conducted finding tumoral membranes attached to the internal layer of the duramater around the right hemisphere. The patient died a few days later due to the recurrence of the subdural hematoma. This case report illustrates a rare and lethal complication of an unusual tumor. The literature reviewed shows that gross-total resection with adjuvant radiotherapy seems to be the best treatment of choice.

Angiosarcoma: clinical and imaging features from head to toe

Angiosarcoma is a rare, aggressive subtype of soft-tissue sarcoma with a propensity for local recurrence and metastasis associated with a generally poor prognosis, unless diagnosed early. Given the vascular endothelial cell origin of angiosarcoma, tumours may develop in essentially any organ; however, there is a predilection for the skin where half of all tumours arise, increasing in prevalence with age. The most common risk factors are chronic lymphoedema and history of radiation. We review the most important radiological findings along the spectrum of angiosarcoma from head to toe throughout the body, including uncommon and rare locations. Key imaging features of angiosarcoma across multiple organ systems will be described, as well as the impact on management and prognosis.

Primary Angiosarcoma of the Central Nervous System: Case Report and Review of the Imaging Features

Primary angiosarcoma of the central nervous system is a rare malignant tumor with only 28 reported cases so far. Imaging findings have only been reported in a few cases. We report a case of intracranial angiosarcoma in a Caucasian male and present a review of the imaging features in the recent literature. The tumor mostly presents as a well-demarcated, heterogeneous, moderately to strongly enhancing lesion with signs of intratumoral bleeding and surrounding vasogenic edema. The differential imaging features of common hemorrhagic intracranial tumors are discussed.

Radiation-induced angiosarcoma of the brain

Primary angiosarcoma of the central nervous systemis unusual.We encountered a case of radiation-induced angiosarcoma of the brain. A 65-year-old male was referred to our hospital with drowsiness for the last 6 months. He had undergone radiation therapy for pituitary adenoma 43 years ago. An MRI revealed a right temporal lobe tumour that consisted of a well-demarcated haemorrhagic lesion and an avid contrast enhancement, with significant vasogenic oedema. Surgical resection was performed and a post-operative pathological diagnosis of an angiosarcoma was made. A Thorotrast-associated angiosarcoma has been, hitherto, the only reported case of radiation-induced angiosarcoma of the brain. We present an extremely rare case of primary angiosarcoma of the brain, occurring after external beam radiotherapy.

Primary central nervous system angiosarcoma: a case report and literature review

Angiosarcoma is a rare vascular malignant neoplasm that mainly occurs in skin and soft tissues. Intracranial localization is very rare and only a few cases have been reported. This report intends to present the clinical, radiological and pathological pictures of a primary central nervous system angiosarcoma along with a review of the literature. A 35-year-old woman presented at our institution with weakness and sensory disturbances of her right hand. Neuroimaging revealed a roughly round, hemorrhagic and moderately enhancing lesion in the left frontal posterior region. The tumor was totally removed under awake anesthesia and continuous monitoring of motor and language functions. Histopathology revealed an epithelioid angiosarcoma. Radical removal, followed by adjuvant radiotherapy and chemotherapy, is able to completely control the disease for a relatively long period.

Primary central nervous system angiosarcoma: two case reports

Introduction

Primary angiosarcoma of the brain is extremely rare; only 15 cases have been reported in adults over the last 25 years.

Case presentations

We describe two cases of primary angiosarcoma of the brain that are well characterized by imaging, histopathology, and immunohistochemistry. Case 1: our first patient was a 35-year-old woman who developed exophthalmos. Subtotal resection of a left extra-axial retro-orbital mass was performed. Case 2: our second patient was a 47-year-old man who presented to our facility with acute visual loss, word-finding difficulty and subtle memory loss. A heterogeneously-enhancing left sphenoid wing mass was removed. We also review the literature aiming at developing a rational approach to diagnosis and treatment, given the rarity of this entity.

Conclusions

Gross total resection is the standard of care for primary angiosarcoma of the brain. Adjuvant radiation and chemotherapy are playing increasingly recognized roles in the therapy of these rare tumors.

Rapid clinical course of cerebral metastatic angiosarcoma from the heart

We report here one case of rapid and aggressive course of cerebral metastatic angiosarcoma from the heart. A 36-year-old man presented with 10-days history of headache. Magnetic resonance imaging demonstrated subacute hemorrhage with a small region of enhancement in right parietal region and the pathological diagnosis was angiosarcoma. Transthoracic echocardiography demonstrated 3.2×3 cm sized mass on right atrial wall. Newly developed lesion was reoperated, three and four weeks later respectively, and whole brain radiotherapy of total 30 Gy was done. With the interval of two months, gamma knife surgery was done for new lesions two times, which were well controlled. Newly developed lesions rapidly happened even in the adjuvant treatment. He died 9 months after the diagnosis because of the aggravation of primary cancer. The cerebral metastatic angiosarcoma from the heart showed the rapid aggressive behavior and the closed follow-up could be needed for the adjuvant treatment.

Primary intramedullary spinal sarcoma : a case report and review of the current literatures

Primary central nervous system (CNS) sarcomas are exceedingly rare, and, to the best of our knowledge, there has not yet been a report of intramedullary sarcoma. Here, we report a primary intradural intramedullary sarcoma of the spinal cord in a four-year-old boy who presented with low back pain and a radiculopathy involving both lower extremities. The tumor showed significant enhancement on magnetic resonance (MR) images due to its extreme vascularity. Gross total tumor removal was performed with microelectrical pulse recording, and the patient also received adjuvant radiotherapy and chemotherapy. After the operation, the patient's sensory deficits were improved. Because CNS dissemination is common, entire neuraxis evaluation is essential, although there was no evidence of dissemination in this case. The prognosis of primary CNS sarcoma is poor due to infiltrative nature and early CNS dissemination is common, and the treatment of choice is radical surgical resection. Adjuvant therapy is also beneficial with radiotherapy and chemotherapy.

Intracranial invasion from recurrent angiosarcoma of the scalp

Angiosarcoma of the brain, either primary or metastatic is extremely rare. Moreover, angiosarcoma metastasizing to the brain is also highly unlike to occur comparing with metastases to the other organs. Thus, an ideal treatment strategy has not been established. A 67-year-old man with past surgical history of a scalp angiosarcoma underwent surgical resection of intracranial invasion. Because of wide scalp flap excision and resultant poor vascularity of the scalp flap, additional radiation was not provided. Because adjuvant therapy is impossible due to poor scalp condition, more careful but ample resection of the primary lesion is essential to conduct initial operation.

Primary angiosarcoma of the brain in a child

We describe a pediatric case of primary angiosarcoma of the brain displaying striking intravascular papillary pattern, consistent with the "Dabska tumor," often in continuity with a massive, multifocal intravascular papillary endothelial hyperplasia. The tumor contained small hemangioma and obliterated dysplastic arteries as well as very large thin-walled veins. The surrounding brain tissue showed scattered telangiectasias, conglomerates of calcified dysplastic arteries, old hemorrhages and gliosis. Colocalization of these lesions suggests the development of a papillary angiosarcoma in the pre-existing vascular malformation. Although never reported, the possibility of a malignant transformation of endothelial papillary hyperplasia also should be considered in this case.

A diagnostic pitfall: Angiosarcoma of the brain mimicking cavernous angioma

Primary or secondary angiosarcoma in the central nervous system is rarely reported. We present a rare case of cerebral angiosarcoma, which comprised both poorly-differentiated solid areas and well-differentiated areas that led to the misdiagnosis of cavernous angioma. A 79-year old woman presented with an intracerebral hematoma in the left frontal lobe that was misdiagnosed as a hemorrhage from a cavernous angioma at initial operation. At a second surgery, the lesion was diagnosed as angiosarcoma involving the cerebellum, heart, femur, sacro-iliac bones and other locations. An autopsy suggested that the angiosarcoma of the heart was the primary lesion, which was occult at the time of the initial operation. Angiosarcoma may have areas with different degrees of differentiation and when a cavernous angioma is suspected histopathologically, the specimen should also be carefully explored for poorly-differentiated areas and the diagnosis of primary or secondary angiosarcoma considered.

Cerebral metastasis from angiosarcoma of the aortic wall: case report

BACKGROUND

Primary or metastatic cerebral angiosarcoma is extremely rare, and only limited cases have been reported. The authors here describe a case of angiosarcoma, which was initially identified and diagnosed by the cerebral metastatic lesion; later examinations suggested that the primary site was the abdominal aorta.

CASE DESCRIPTION

A 53-year-old man, who had suffered an abdominal aortic aneurysm 2 months earlier, experienced a sudden onset of left-sided hemifacial convulsion and dysarthric speech. Computed tomography (CT) showed a hemorrhagic mass lesion with perifocal edema in the right frontal lobe. Magnetic resonance imaging (MRI) showed a regionally marked hypointensity in the mass lesion on both T1- and T2-weighted images, which might suggest hemosiderin deposition. The tumor was removed in its entirety. Pathologic examination revealed an old hematoma with a hemosiderin deposit containing markedly atypical tumor cells, and angiosarcoma was diagnosed. Resection of the abdominal aortic aneurysm and iliac bone biopsy were performed and angiosarcoma was recognized in each surgical specimen. Based on clinical and pathologic findings, the primary site was considered to be the abdominal aorta.

CONCLUSIONS

Clinicians should be aware of this rare histologic type of tumor. Unique MRI findings such as those obtained in our case might be useful for differentiating this condition from other intracranial neoplasms.

Primary sarcomas of the brain and spinal cord: a study of 18 cases

Primary sarcomas of the central nervous system are exceedingly rare. We reviewed the clinicopathologic features of 18 primary central nervous system sarcomas diagnosed from 1959 through 1999. Median age at diagnosis of the nine female and nine male patients was 28 years (range 3-63 years). Median tumor size was 4 cm (range 1.3-8 cm). Fifteen tumors arose in the cerebrum (83%), two in the cerebellum, and one in the spinal cord. Histopathologically, the most common tumor types included fibrosarcoma (six), malignant fibrous histiocytoma (five), and undifferentiated sarcoma (three). Immunohistochemical and ultrastructural studies supported the histologic diagnosis in 17 and six cases, respectively. All patients had subtotal to gross total tumor resection; 16 also received radiotherapy and/or chemotherapy. Twelve tumors (67%) were high-grade. Follow-up was obtained in all instances (median 2.3 years). Nine patients died of the disease, eight with high-grade tumors. Survival at 5 years for patients with high-grade tumors was 28% compared with 83% for those with low-grade neoplasms (p = 0.03). Primary central nervous system sarcomas most often affect young and middle-aged adults. Most involve the cerebrum and show fibrous, "fibrohistiocytic," or no specific differentiation. The prognosis for high-grade sarcomas seems better than that for glioblastoma multiforme.

Hemorrhage in cerebral metastasis from angiosarcoma of the heart: case report

The purpose of this article is to describe the clinical and pathological features of metastatic angiosarcoma in the central nervous system. Only a few cases of cerebral metastasis from angiosarcoma of the heart have been recorded in the literature; particularly related to intracerebral hemorrhage. A case of secondary cerebral angiosarcoma of the heart in a 33 years old man is presented. The initial symptoms were headache, vomiting, lethargy and aphasia. There was a mass in the left temporal lobe with hemorrhage and edema on the computerized tomography (CT). After 24 hours the neurological status worsened and another CT scan showed rebleeding on the tumor area. He underwent an emergency craniotomy but died two days after. Considering the longer survival of sarcoma patients with new modalities of treatment, the incidence of brain metastasis may increase, demanding a better preventive and more aggressive approach. Besides, due to the hemorrhagic nature of such lesions, we suggest the immediate surgery to prevent a fast and lethal evolution because rebleeding.

Gliosarcoma with angiosarcomatous features: a case report

A surgical case of gliosarcoma in which the mesenchymal component showed angiosarcomatous features is reported. The neoplasm was extirpated from the right cerebral hemisphere of a 76-year-old man who presented with left hemiparesis and headache, and it was composed of both anaplastic astrocytomatous and sarcomatous elements. The sarcomatous element was composed of a proliferation of atypical endothelial cells that had pleomorphic, mitotically active nuclei and formed vascular lumina of irregular shapes or solid cellular sheets, and was accompanied by the deposition of collagenous matrix. The cytoplasm of some of the atypical endothelial cells was immunohistochemically positive for vimentin, factor VIII-related antigen, CD 34, and thrombomodulin. The MIB-1 labeling index of the sarcomatous component was higher than that of the astrocytomatous component.

Intravascular papillary endothelial hyperplasia of the sellar region. Report of three cases and review of the literature

Intravascular papillary endothelial hyperplasia (IPEH) is considered a reactive proliferation of endothelium associated with thrombosis. The occurrence of IPEH in the cranial cavity is exceedingly rare. In this article, the authors report three cases of IPEH that originated from the cavernous sinus and extended into the sellar contents. The lesions were resected incompletely in two cases and completely in one case. The IPEH in one of the patients was incompletely resected and exhibited further growth on magnetic resonance imaging 3 months postoperatively; local radiation therapy was instituted. This led to shrinkage of the lesion over an additional follow-up period of 3.5 years. In a review of the literature, the authors located seven other cases of intracranial IPEH. The authors conclude that clinically symptomatic intracranial IPEH should be completely resected whenever possible, because it can cause considerable morbidity and mortality and because it is prone to progression or recurrence.

Primary angiosarcoma of the brain: case report

A 41-year-old patient with a primary angiosarcoma of the brain is reported. The tumor was located in the left parietal lobe and was radically removed. The diagnosis of angiosarcoma was established by immunohistochemistry. The patient was postoperatively treated with adjuvant chemotherapy and then radiation therapy. After 41 months, she was in excellent clinical and neurological condition without any sign of recurrence.

Primary intracranial pleomorphic angioleiomyoma--a new morphologic variant. An immunohistochemical and electron microscopic study

BACKGROUND

Angioleiomyomas usually are benign subcutaneous neoplasms that occur most often in extremities of middle-aged individuals. Very few cases have been described in other locations; none along the neuroaxis. An intracranial example of angioleiomyoma displaying unusual morphologic features not seen in the typical peripheral variants of this tumor is described.

METHODS

The tumor was studied with conventional histology, immunohistochemistry with morphometric calculation of proliferation index, immunoelectron microscopy, and DNA flow cytometry.

RESULTS

The tumor was composed of large epithelioid and pleomorphic cells filled with intermediate filaments positive for desmin and vimentin. Scattered cells also expressed myosin and muscle-specific actin. Smooth muscle cell differentiation was confirmed by ultrastructural demonstration of subplasmalemmal dense bodies, attachment plaques, and discontinuous basal lamina. The proliferation index with proliferating cell nuclear antigen (PCNA) monoclonal antibody was 75.78%, whereas it was only 4.22% with Ki67 monoclonal antibodies adopted to paraffin material (MIB-1).

CONCLUSION

The tumor represents a unique morphologic variant of a pleomorphic angioleiomyoma. Cellular pleomorphism and a strong reaction for PCNA in numerous cells suggested that the lesion was malignant. However, the absence of mitotic figures, a small number of Ki-67-positive cells, a diploic DNA pattern, and a low proliferation index in flow cytometry all supported the concept that this neoplasm represented an unusual histologic variant of benign angiogenic leiomyoma. Encapsulation and demarcation of the surgical specimen and the survival of the patient for more than 4 years without recurrence after resection support this interpretation.

The application of 5-bromodeoxyuridine in the management of CNS tumors

A variety of clinical reports have described the application of the bromodeoxyuridine labeling index as an adjunct to conventional pathological examination of CNS tumors. This index has proven useful in predicting the clinical outcome associated with many such tumors. Furthermore, because of its efficacy as a radiosensitizing agent, bromodeoxyuridine (and the closely related iododeoxyuridine) has been used in combination with radiation therapy for malignant glial neoplasms, with some encouraging results. Although most studies suggest that bromodeoxyuridine is safe, there is evidence that this compound does have potential side-effects, including the observation that it is a mutagen and carcinogen in some experimental systems. A number of new alternative approaches for predicting the clinical outcome of CNS tumors has been developed based on an increased understanding of their molecular biology. However, until such approaches are better characterized, the clinical application of bromodeoxyuridine will continue to play an important role in predicting the clinical behavior of many CNS tumors.

The growth of two murine hemangioendotheliomas intracranially, subcutaneously, and in culture, and their comparison with human cerebellar hemangioblastomas: morphological and immunohistochemical studies

Two thorium dioxide-induced murine hemangioendotheliomas, 42021 TCT and 44347 TST, were grown subcutaneously (for up to 22 and 15 passages respectively) or intracranially (single passage) and were adapted to culture as a monolayer and, in a limited fashion, in an organ culture system or in rotary suspension. They remained viable and malignant following 20-21 years of storage in liquid nitrogen, and had ultrastructural similarities to human hemangioblastomas. The murine tumors were positive for Griffonia (Bandeiraea) simplicifolia isolectin B4 binding, establishing their endothelial nature; however, unlike human hemangioblastic tumors, they did not cross-react with antisera to human factor VIII or fibronectin and they did not demonstrate Ulex europaeus type I lectin (UEA I) binding (as is also the case for non-neoplastic murine vascular endothelial cells). A variety of morphological cell types in cultures derived from the tumors were also positive for Griffonia (Bandeiraea) simplicifolia isolectin B4 binding. Both murine hemangioendotheliomas, when implanted in the cerebrum, were potent inducers of reactive gliosis, but there was no evidence of uptake of glial fibrillary acidic protein. Unlike the human cerebellar hemangioblastomas, murine tumors were malignant and invasive and did not contain stromal cells, nor did they demonstrate Weibel-Palade bodies or extensive pinocytotic activity. Thus, the murine tumors appear to more closely resemble angiosarcomas or epitheloid hemangioblastomas than the cerebellar hemangioblastomas.

Primary angiosarcoma of the central nervous system. Study of eight cases and review of the literature

Angiosarcoma arising in the central or peripheral nervous system has rarely been reported. Eight patients with primary angiosarcoma of the central nervous system are described here; these included five males and three females ranging in age from 2 weeks to 72 years (mean 38 years). Of the eight neoplasms, six were located in the cerebral hemispheres and one was in the meninges; the site was unknown in the other. All patients underwent surgical resection. Five of the eight patients died, four within 4 months after surgery and one after 30 months. Two of the remaining three patients were 17 and 27 years old at the time of diagnosis and were alive at follow-up review 39 and 102 months after surgery, respectively. One patient was lost to follow-up monitoring. Microscopically, all eight tumors demonstrated a well-differentiated pattern with irregular vascular channels and intraluminal papillae; in addition, four showed poorly differentiated solid areas. Immunohistochemical staining of neoplastic cells to factor VIII-related antigen and Ulex europaeus agglutinin I was performed in five tumors and was focally positive in four. No correlation could be shown between the histological features and the growth and biological behavior of the tumors.

Primary intracranial sarcomas: histopathological features of 19 cases

Nineteen primary intracranial sarcomas out of a total of about 25,000 brain tumour biopsies are reported. Subtypes included malignant fibrous histiocytoma (6 cases), leiomyosarcoma (3), rhabdomyosarcoma (2), angiosarcoma (2), and one case each of fibrosarcoma, low-grade fibromyxoid sarcoma, malignant ectomesenchymoma, mesenchymal chondrosarcoma, differentiated chondrosarcoma and Ewing's sarcoma. Histological and immunohistochemical features corresponded to those of extracranial sarcomas. Nests of pleomorphic astrocytes mimicking glioma were detected in the five storiform-pleomorphic malignant fibrous histiocytomas. Our results indicate that intracranial sarcomas can be classified like their extracranial counterparts. The low incidence compared with earlier series is related to changes in classification and progress in histogenetic clarification.

Metastatic angiosarcoma of the brain

Two patients with metastatic angiosarcoma of the brain are described. In one, a 17-year-old man, the tumor was located at the pineal region and exhibited significant vascularity. It was sensitive to radiation therapy and disappeared after radiation of 50 Gy; however, it recurred after 1 year and a new lesion was found in the liver. The other patient is a 31-year-old woman who experienced sudden onset of headache. Computed tomography scan revealed three separate masses in the brain. One tumor was surgically removed. The other two were sensitive to radiation therapy and disappeared after radiation of 40 Gy. A new lesion was found in the femur 16 months after the operation. Brain metastasis from angiosarcoma is exceedingly rare. Both patients developed symptoms with intracranial hemorrhage. The diagnosis of the metastatic lesions preceded diagnosis of the primary lesion by 12 and 16 months, respectively. Ulex europaeus 1 lectin and factor VIII were very useful in establishing the diagnosis of angiosarcoma.

Mesenchymal, non-meningothelial tumors of the central nervous system

The spectrum of non-meningothelial mesenchymal tumors that may arise within the central nervous system is presented, based on the current classification of soft tissue tumors. Among malignant types, hemangiopericytoma, rhabdomyosarcoma, mesenchymal chondrosarcoma, and malignant fibrous histiocytoma are the most frequent ones. Rare tumor entities are mentioned. As in soft tissue sarcomas, diagnosis is mainly based on light and electron microscopy, while immunohistochemistry can improve accuracy of diagnosis.

Cerebral metastasis from angiosarcoma of the heart. Case report

A case of secondary cerebral angiosarcoma in a 30-year-old man is presented. The patient had previously undergone heart transplantation for treatment of the primary tumor. Only a few cases of cerebral metastasis from angiosarcoma have been recorded in the literature; the present case is the first reported case diagnosed after heart transplantation.

Intracranial lesions in dogs with hemangiosarcoma

A retrospective analysis of 85 dogs with hemangiosarcoma (HSA) that underwent complete necropsy, including gross examination of the brain, was conducted. Grossly identifiable intracranial lesions were present in 17 dogs. Twelve of 85 dogs (14.2%) had brain metastases. Four of 85 dogs (4.7%) had hemorrhagic lesions and/or ischemic necrosis without identifiable tumor. One dog had a primary central nervous system tumor. Signs of intracranial disease were present in six of 85 dogs (7.1%) with HSA; four had brain metastases and two had nonneoplastic lesions. Metastases had a propensity for cerebrum and gray matter. Dogs with brain metastases had more widely disseminated disease than dogs without brain metastases (P less than 0.001). Dogs with pulmonary metastases were at greater risk for developing brain metastases than dogs without pulmonary metastases (odds ratio = 8.31). Although thoracic radiography accurately identified ten of 12 dogs (83%) with pulmonary metastases, too few cases were available to assess the applicability/accuracy of thoracic radiography in predicting the presence or absence of brain metastases in dogs with malignancy and signs of intracranial disease.

Ultrastructural and immunocytochemical observations on angiosarcomas

Forty-seven angiosarcomas have been studied by light and electron microscopy. Neoplastic endothelial cells do not consistently display specific ultrastructural features, but certain aspects of the fine structure of the cells and their arrangement can be useful to establish or confirm the diagnosis. Experience with the common endothelial cell markers as diagnostic aids is briefly reviewed.