A tumor composed of spindle cells with a rich vascular network, which apparently arises from pericytes, cells of smooth muscle origin that lie around small vessels. Benign and malignant hemangiopericytomas exist, and the rarity of these lesions has led to considerable confusion in distinguishing between benign and malignant variants. (From Dorland, 27th ed; DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1364)
Benign and malignant neoplastic processes that arise from or secondarily involve the meningeal coverings of the brain and spinal cord.
Neoplasms located in the brain ventricles, including the two lateral, the third, and the fourth ventricle. Ventricular tumors may be primary (e.g., CHOROID PLEXUS NEOPLASMS and GLIOMA, SUBEPENDYMAL), metastasize from distant organs, or occur as extensions of locally invasive tumors from adjacent brain structures.
Cancer or tumors of the MAXILLA or upper jaw.
A double-layered fold of peritoneum that attaches the STOMACH to other organs in the ABDOMINAL CAVITY.
Rare neoplasms of mesenchymal origin, usually benign, and most commonly involving the PLEURA (see SOLITARY FIBROUS TUMOR, PLEURAL). They also are found in extrapleural sites.
A benign tumor composed of fat cells (ADIPOCYTES). It can be surrounded by a thin layer of connective tissue (encapsulated), or diffuse without the capsule.
A relatively common neoplasm of the CENTRAL NERVOUS SYSTEM that arises from arachnoidal cells. The majority are well differentiated vascular tumors which grow slowly and have a low potential to be invasive, although malignant subtypes occur. Meningiomas have a predilection to arise from the parasagittal region, cerebral convexity, sphenoidal ridge, olfactory groove, and SPINAL CANAL. (From DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, pp2056-7)

Haemangiopericytoma in the distal third of the arm. (1/145)

A 49-year-old woman had a haemangiopericytoma in the distal third of the arm, which is an extremely rare location. There was no recurrence of the tumor 5 years after wide margin surgical excision.  (+info)

Measurement of telomerase activity in dog tumors. (2/145)

Telomeres are specific structures present at the end of liner chromosomes. DNA polymerase can not synthesize the end of liner DNA and, as a result, the telomeres become progressively shortened by successive cell divisions. To overcome the end replication problem, telomerase adds new telomeric sequences to the end of chromosomal DNA. The enzyme activity is undetectable in most normal human adult somatic cells, in which shortening of the telomere is thought to limit the somatic-cell life span. In contrast to normal somatic cells, many human tumors possess telomerase activity. The present study looked at whether telomerase activity might serve as a marker for canine tumors. Telomerase activity was measured using the telomeric repeat amplification protocol assay. Normal dog somatic tissues showed little or no telomerase activity, while normal testis exhibited a high level of telomerase activity. We measured telomerase activity in tumor samples from 45 dogs; 21 mammary gland tumors, 16 tumors developed in the skin and oral cavity, 7 vascular tumors and 1 Sertoli cell tumor. Greater than 95% of the tumor samples contained telomerase activity (3-924 U/2 micrograms protein). The results obtained in this study indicated that telomerase should be a useful diagnostic marker for a variety of dog tumors, and it may serve as a target for antitumor chemotherapy.  (+info)

Haemangiopericytoma of kidney: a report of 2 cases. (3/145)

Haemangiopericytoma is a rare neoplasm of the kidney. There are no unique radiological or clinical identifiers that can aid in preoperative diagnosis. Surgery is the only reliable therapy, as both chemotherapy and radiotherapy have proven ineffective in several series. The outcome is difficult to predict, the only reliable predictor is presence or absence of metastasis. The rarity of this lesion prompts the report of these two cases.  (+info)

Liver angiosarcoma and hemangiopericytoma after occupational exposure to vinyl chloride monomer. (4/145)

Various malignant tumors of the liver, especially liver angiosarcoma, have been described after occupational exposure to vinyl chloride monomer. We present the case records and pathologic findings of two plastic industry workers who had been exposed to high concentrations of vinyl chloride. These workers developed hepatic neoplasms, angiosarcoma, or hemangiopericytoma. We discuss the histogenesis of these tumors; the common vascular origin and the mutual transformation of these two tumors suggest that the hemangiopericytoma may also have developed during occupational exposure to high concentrations of vinyl chloride monomer.  (+info)

Solitary fibrous tumor arising from the falx cerebri--case report. (5/145)

A 50-year-old female was admitted with headache and visual disturbance. Neuroimaging demonstrated a well-demarcated large tumor attached to the falx cerebri. The tumor was totally removed by surgery. Histological examination showed that the tumor consisted of spindle cells with no pattern in the collagenous background. Staghorn-like blood vessels were common. Immunohistochemical study showed the tumor cells were strongly positive for CD34 and vimentin, but negative for epithelial membrane antigen. The diagnosis was solitary fibrous tumor arising from the falx cerebri. Solitary fibrous tumor is rare within the cranial cavity, and can be distinguished from meningioma and hemangiopericytoma by the histological, ultrastructural, and immunohistochemical findings.  (+info)

Prostaglandin D synthase (beta-trace) in meningeal hemangiopericytoma. (6/145)

The level of prostaglandin D synthase (PGDS), a major protein constituent of cerebrospinal fluid (CSF), is altered in various brain diseases, including meningitis. However, its role in the brain remains unclear. PGDS is mainly synthesized in the arachnoid cells, the choroid plexus and oligodendrocytes in the central nervous system. Among brain tumors, meningiomas showed intense immunoreactivity to PGDS in the perinuclear region. Thus, PGDS has been considered a specific cell marker of meningioma. In this study, we examined 25 meningeal hemangiopericytomas (HPCs) and found that 16 of the tumors (64%) showed immunoreactivity for PGDS in the perinuclear region. For comparison, 15 meningiomas, 14 soft-tissue HPCs, 1 mesenchymal chondrosarcoma, 3 choroid plexus papillomas, and 7 oligodendrogliomas were also examined. Meningiomas showed positive immunoreactivity for PGDS in 13 cases (80%). Except for one case located at the sacrum, none of the other soft-tissue HPCs showed immunostaining for PGDS. Mesenchymal chondrosarcoma arises in the bones of the skull, and its histological pattern resembles that of HPC; however, it showed no immunoreactivity for PGDS. Neither choroid plexus papillomas nor oligodendrogliomas were immunopositive for PGDS. These findings suggest that meningeal HPCs may have a unique molecular phenotype that is distinct from that of the soft-tissue HPCs. The origin of meningeal HPCs may be more closely related to the arachnoid cells.  (+info)

Recurrent congenital haemangiopericytoma in a child. (7/145)

A five-day-old boy was referred with a soft-tissue mass in his right upper arm. Plain radiographs and ultrasound demonstrated a lesion extending from the axilla to the elbow on the posterolateral aspect of the humerus. Open biopsy confirmed the diagnosis of congenital haemangiopericytoma. After MRI and selective angiography, excision biopsy was carried out, but no adjuvant therapy was administered. At further examination, four years and ten months later, he was noted to have three small nodules at the site of the original tumour. Excision biopsy confirmed this to be a local recurrence, although the lesion was less cellular with no appreciable mitotic activity. Congenital haemangiopericytoma is a rare cause of a soft-tissue mass in children. Most tumours are benign, and recurrence is uncommon. The treatment is controversial, but most centres recommend the use of adjuvant chemotherapy, combined with complete excision. We recommend treatment with doxorubicin. Orthopaedic surgeons should be familiar with this tumour since 30% to 50% of cases occur in the limbs.  (+info)

Cloning and characterization of FGF23 as a causative factor of tumor-induced osteomalacia. (8/145)

Tumor-induced osteomalacia (TIO) is one of the paraneoplastic diseases characterized by hypophosphatemia caused by renal phosphate wasting. Because removal of responsible tumors normalizes phosphate metabolism, an unidentified humoral phosphaturic factor is believed to be responsible for this syndrome. To identify the causative factor of TIO, we obtained cDNA clones that were abundantly expressed only in a tumor causing TIO and constructed tumor-specific cDNA contigs. Based on the sequence of one major contig, we cloned 2,270-bp cDNA, which turned out to encode fibroblast growth factor 23 (FGF23). Administration of recombinant FGF23 decreased serum phosphate in mice within 12 h. When Chinese hamster ovary cells stably expressing FGF23 were s.c. implanted into nude mice, hypophosphatemia with increased renal phosphate clearance was observed. In addition, a high level of serum alkaline phosphatase, low 1,25-dihydroxyvitamin D, deformity of bone, and impairment of body weight gain became evident. Histological examination showed marked increase of osteoid and widening of growth plate. Thus, continuous production of FGF23 reproduced clinical, biochemical, and histological features of TIO in vivo. Analyses for recombinant FGF23 products produced by Chinese hamster ovary cells indicated proteolytic cleavage of FGF23 at the RXXR motif. Recent genetic study indicates that missense mutations in this RXXR motif of FGF23 are responsible for autosomal dominant hypophosphatemic rickets, another hypophosphatemic disease with similar features to TIO. We conclude that overproduction of FGF23 causes TIO, whereas mutations in the FGF23 gene result in autosomal dominant hypophosphatemic rickets possibly by preventing proteolytic cleavage and enhancing biological activity of FGF23.  (+info)

Hemangiopericytoma is a rare type of soft tissue sarcoma, which is a cancer that develops from the cells that surround blood vessels. It specifically arises from the pericytes, which are cells that help regulate blood flow in capillaries. Hemangiopericytomas typically form in the membranes surrounding the brain and spinal cord (meninges), but they can also occur in other parts of the body such as the lungs, abdomen, or extremities.

These tumors usually grow slowly, but they can become aggressive and spread to other parts of the body (metastasize). Symptoms depend on the location of the tumor, but may include headaches, seizures, weakness, or numbness in the arms or legs. Diagnosis typically involves imaging tests like MRI or CT scans, followed by a biopsy to confirm the presence of cancer cells. Treatment usually consists of surgical removal of the tumor, often accompanied by radiation therapy and/or chemotherapy to help prevent recurrence or spread of the disease.

Meningeal neoplasms, also known as malignant meningitis or leptomeningeal carcinomatosis, refer to cancerous tumors that originate in the meninges, which are the membranes covering the brain and spinal cord. These tumors can arise primarily from the meningeal cells themselves, although they more commonly result from the spread (metastasis) of cancer cells from other parts of the body, such as breast, lung, or melanoma.

Meningeal neoplasms can cause a variety of symptoms, including headaches, nausea and vomiting, mental status changes, seizures, and focal neurological deficits. Diagnosis typically involves imaging studies (such as MRI) and analysis of cerebrospinal fluid obtained through a spinal tap. Treatment options may include radiation therapy, chemotherapy, or surgery, depending on the type and extent of the tumor. The prognosis for patients with meningeal neoplasms is generally poor, with a median survival time of several months to a year.

Cerebral ventricle neoplasms refer to tumors that develop within the cerebral ventricles, which are fluid-filled spaces in the brain. These tumors can arise from various types of cells within the ventricular system, including the ependymal cells that line the ventricles, choroid plexus cells that produce cerebrospinal fluid, or other surrounding tissues.

Cerebral ventricle neoplasms can cause a variety of symptoms depending on their size and location, such as headaches, nausea, vomiting, vision changes, imbalance, weakness, or difficulty with mental tasks. The treatment options for these tumors may include surgical resection, radiation therapy, and chemotherapy, depending on the type and extent of the tumor. Regular follow-up care is essential to monitor for recurrence and manage any long-term effects of treatment.

Maxillary neoplasms refer to abnormal growths or tumors in the maxilla, which is the upper jaw bone. These growths can be benign (non-cancerous) or malignant (cancerous). Benign neoplasms are slow-growing and do not spread to other parts of the body, while malignant neoplasms can invade surrounding tissues and spread to distant sites.

Maxillary neoplasms can cause various symptoms such as swelling, pain, numbness, loose teeth, or difficulty in chewing or swallowing. They may also cause nasal congestion, nosebleeds, or visual changes if they affect the eye or orbit. The diagnosis of maxillary neoplasms usually involves a combination of clinical examination, imaging studies such as CT or MRI scans, and biopsy to determine the type and extent of the tumor.

Treatment options for maxillary neoplasms depend on several factors, including the type, size, location, and stage of the tumor, as well as the patient's overall health and preferences. Treatment may include surgery, radiation therapy, chemotherapy, or a combination of these modalities. Regular follow-up care is essential to monitor for recurrence or metastasis and ensure optimal outcomes.

The omentum, in anatomical terms, refers to a large apron-like fold of abdominal fatty tissue that hangs down from the stomach and loops over the intestines. It is divided into two portions: the greater omentum, which is larger and hangs down further, and the lesser omentum, which is smaller and connects the stomach to the liver.

The omentum has several functions in the body, including providing protection and cushioning for the abdominal organs, assisting with the immune response by containing a large number of immune cells, and helping to repair damaged tissues. It can also serve as a source of nutrients and energy for the body during times of starvation or other stressors.

In medical contexts, the omentum may be surgically mobilized and used to wrap around injured or inflamed tissues in order to promote healing and reduce the risk of infection. This technique is known as an "omentopexy" or "omentoplasty."

Solitary fibrous tumors (SFTs) are rare type of slow-growing neoplasms that typically arise from the pleura, the thin layer of tissue that covers the lungs. However, they can also occur in other locations throughout the body such as the peritoneum, meninges, and deep soft tissues.

SFTs are composed of spindle-shaped cells arranged in a patternless architecture, with a variably collagenous stroma. They are usually well-circumscribed and encapsulated, although they can become invasive in some cases. The cellularity of SFTs varies from low to high, and the tumors can contain staghorn vessels, which are dilated blood vessels with a branching pattern.

The majority of SFTs are benign, but approximately 10-20% of them can be malignant or have aggressive behavior, with potential for local recurrence and distant metastasis. The diagnosis of SFT is usually made by histopathological examination of the tumor tissue, which shows characteristic features such as CD34 and Bcl-2 positivity on immunohistochemistry.

Treatment options for SFTs include surgical resection with wide margins, radiation therapy, and systemic therapy with chemotherapy or targeted agents. The choice of treatment depends on the location, size, and behavior of the tumor, as well as the patient's overall health status. Regular follow-up is necessary to monitor for recurrence or metastasis.

A lipoma is a common, benign (non-cancerous) soft tissue growth. It is composed of adipose or fatty tissue and typically found just beneath the skin, but they can also occur deeper within the body. Lipomas are usually round, moveable, and painless, although they may cause discomfort if they grow large enough to put pressure on nearby nerves or if they're located in a sensitive area. They generally grow slowly over time. Surgical removal is an option if the lipoma becomes bothersome or grows significantly in size. It's important to note that while lipomas are typically harmless, any new lumps or bumps should be evaluated by a healthcare professional to confirm the diagnosis and rule out other more serious conditions.

A meningioma is a type of slow-growing tumor that forms on the membranes (meninges) surrounding the brain and spinal cord. It's usually benign, meaning it doesn't spread to other parts of the body, but it can still cause serious problems if it grows and presses on nearby tissues.

Meningiomas most commonly occur in adults, and are more common in women than men. They can cause various symptoms depending on their location and size, including headaches, seizures, vision or hearing problems, memory loss, and changes in personality or behavior. In some cases, they may not cause any symptoms at all and are discovered only during imaging tests for other conditions.

Treatment options for meningiomas include monitoring with regular imaging scans, surgery to remove the tumor, and radiation therapy to shrink or kill the tumor cells. The best treatment approach depends on factors such as the size and location of the tumor, the patient's age and overall health, and their personal preferences.

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