Hemangiopericytoma is an uncommon mesenchymal tumor that may be benign or malignant. This tumor is composed of proliferating capillaries and spindle-shaped cells known as the pericytes of Zimmermann. Since all capillaries have pericytes, hemangiopericytoma can be found anywhere In the body. We report a case of malignant hemangiopericytoma in the pelvic cavity which was treated by radical excision and adjutant radiotherapy and discuss the clinicopathological feature, prognosis, and therapy of this lesson.
Capillaries ; Hemangiopericytoma* ; Pericytes ; Prognosis ; Radiotherapy

Tumors of vascular origin are subdivided into two groups: those composed of pericytes (hemangiopericytoma and glomus tumor), and those composed of endothelial cells(hemangioendothelioma). They are uncommon, potentially malignant tumors, and in the lung, the tumors may present as a small asymptomatic nodule or a large symptomatic lesion. Recently we experienced two cases of solitary pulmonary vascular tumors(epithelioid hemangioendothelioma and hemangiopericytoma), and reviewed them with references
Hemangioendothelioma ; Hemangioma ; Hemangiopericytoma ; Lung ; Pericytes ; Vascular Neoplasms

We have experienced one case of lymphangioma and one case of lymphangiectasia which was diagnosed with the histopathologic studies, including immunofluorescent and electron microscopic methods. The distribution of Ig G and Ig A within the stroma was shown, particularly in the inflammatory cells. The endothelial lined lymphatic vessel consisted of interrupted basal lamina and absence of pericyte on electron microscope.
Basement Membrane ; Conjunctiva* ; Lymphangioma ; Lymphatic Vessels ; Pericytes

Hemangiopericytoma (HPC) is an uncommon vascular tumor and arises from the proliferation of special cells called pericytes. In 1995, a unique variant of HPC, containing some mature fat, has been first described by Nielsen and was termed lipomatous hemangiopericytoma (LHPC). Clinically, LHPC appears to be indolent, with no recurrences or metastatic spreads. Histologically, LHPC is composed of a variable amount of benign lipomatous and hemangiopericytomatous components. Since the original description, there had been only 2 reports of these tumors, and none in Korea. We report a recent case of lipomatous hemangiopericytoma of the nasal cavity treated by endoscopic excision.
Hemangiopericytoma* ; Korea ; Nasal Cavity* ; Pericytes ; Recurrence

Seven fibrovascular diabetic preretinal membranes were examined with lightmicroscophic immunohistochemical stain and electron-microscopy to evaluate the possibility of pericytes to be involved in membrane contraction. Pericytes were positively stained with anti-actin antibody together with some stromal cells thought to be myofibroblasts presumedly. On transmission electron microscopic study, pericytes were highly active with numerous cytoplasmic processes and contained abundant microfilaments considered as actin in their cytoplasm. Pericyte/endothelial cell ratio of vascular channels were increased in some actively proliferative portion of the membranes. Myofibroblasts that contain abundant cytoplasmic microfilaments were also demonstrated in the extravascular stroma of the membranes and were very similar to the pericytes morphologically. Although the evidence that the pericytes are related to the origin of the myofibroblasts could not be demonstrated, this study suggested that the pericytes may play important roles in development and contraction mechanism of fibrovascular diabetic preretinal membranes.
Actin Cytoskeleton ; Actins ; Cytoplasm ; Membranes* ; Myofibroblasts ; Pericytes* ; Stromal Cells

OBJECTIVE: Hemangiopericytoma is known as a malignant tumor originating from pericytes and rarely occurs in the central nervous system. We present 6 cases of pathologically confirmed meningeal hemangiopericytoma. METHODS: Retrospective study was done based on patient's recordings including radiological studies. Each case of tumors was treated surgically and postoperative radiotherapy was done. RESULTS: There were 5 cases of intracranial and 1 case of spinal hemangiopericytomas. Three of 5 intracranial hemangiopericytomas were located at tentorial region. Total tumor removal was done in 4 cases and postoperative local recurrence (or regrowth) was noted in 3 cases despite of postoperative external radiation therapy, 2 of which had died. CONCLUSION: Our cases show more frequent tentorial locations and poor clinical outcomes of hemangiopericytomas compared with meningiomas.
Central Nervous System ; Hemangiopericytoma* ; Meningioma ; Pericytes ; Radiotherapy ; Recurrence ; Retrospective Studies

Primary hemangiopericytoma of chest wall is very rate and only a few cases have ever been reported. The tumor aries from the capillary pericyte of Zimmerman. It is a highly vascular slow growing tumor which can be calssified as both malignant and benign varieties. We report a case of a 66 year-old man in whom recurrent hemangiopericytoma was treated by complete surgical excision. In October 1993 he had received surgical excision of hemangiopericytoma on posterior chest wall. For more than 6 years after the operation he was in good condition until a recurrent mass was found on the chest X-ray. The patient was discharged 9 days after the operation and is receiving radiotherapy.
Aged ; Capillaries ; Hemangiopericytoma* ; Humans ; Pericytes ; Radiotherapy ; Thoracic Wall* ; Thorax*

The early ultrastructural changes of basement membrane thickening and degeneration of the pericyte were noted in retinal capillaries in diabetic patients. However no early ultrastructural changes were reported in diabetic iris capillary. The authors studied the ultrastructural features of basement membrane of iris capillaries which were obtained during cataract surgery in five diabetic patients and compared with those obtained in five nondiabetic patients. The endothelium basal lamina, pericyte basal lamina and membrane-like pericyte matrix in didabetic iris capillaries were thicker than those in nondiabetic Iris capillaries. The thickening of pericyte basal lamina is more prominant than the endothelium basal lamina in diabetes. The duration of diabetes had no relationship to endothelium basal lamina but, showed statistically significant relationship to thickness of pericyte bascal lamina and pericyte matrix.
Basement Membrane* ; Capillaries* ; Cataract ; Endothelium ; Humans ; Iris* ; Pericytes ; Retinaldehyde

Hemangiopericytoma is a rare vascular tumor that usually occurs in adults. The tumor is believed to originate from pericytes that are closely related to the capillary walls. Congenital hemangiopericytoma is a more rare disease that occurs in approximately 0.03% of all heamngiopericytomas. Herein, we describe a 1-month-old male newborn with huge congenital hemangiopericytoma in the retroperitoneum that exhibited a typical morphological vascular pattern.
Adult ; Capillaries ; Hemangiopericytoma ; Humans ; Infant, Newborn ; Male ; Pericytes ; Rare Diseases

Primary hemangiopericytomas of the lung are uncommon sarcomas that arise from pericytes that surround the basement membrane of capillaries and small venules within the lung parenchyma. The presenting symptoms and signs depend on the location of the tumor and radiologic features are not diagnostic. The behavior of pulmonary hemangiopericytomas is difficult to predict and all tumors should be considered potentially malignant. Wide surgical excision remains the mainstay of treatment. We report a case of primary hemangiopericytoma of the lung with a brief review of literature.
Basement Membrane ; Capillaries ; Hemangiopericytoma* ; Lung* ; Pericytes ; Sarcoma ; Venules