Factor VIII related antigen and glial fibrillary acidic protein immunoreactivity in the differential diagnosis of central nervous system hemangioblastomas

Retroperitoneal peripheral hemangioblastoma: a case report and review of the literature

Central nervous system hemangioblastomas are uncommon tumors of controversial etiology that are usually found in the posterior fossa of the cranial cavity, retina, and spinal cord. Peripheral involvement is rare; only isolated case reports have been identified. We report an unusual case of hemangioblastoma involving the retroperitoneum. A 47-year-old African-American man presented with polycythemia on routine laboratory testing. Computed tomography revealed a large retroperitoneal mass near the pancreas, in a left suprarenal location, without adrenal involvement and without attachment to a nerve. Although hemangioblastoma may be associated with the von Hippel-Lindau syndrome, this patient did not have any of the stigmata of this disease. The histologic features included a highly vascular tumor with cellular areas composed of plump, pleomorphic spindled and epithelioid (stromal) cells with variable cytoplasmic lipid vacuoles and hypocellular areas with inflammatory cells and collagenous fibrils. Immunohistochemical staining showed that the tumor (stromal) cells were positive for vimentin, calponin, S-100 protein, neuron-specific enolase, and CD57 and negative for glial fibrillary acidic protein, cytokeratins, epithelial membrane antigen, CD34, HMB-45, desmin, and the actins. These morphologic and immunohistochemical findings are consistent with hemangioblastoma. To our knowledge this is the first reported case of a hemangioblastoma in this location. Based on this case we conclude that hemangioblastoma may occur in the retroperitoneum and outside of the central nervous system in a patient without von Hippel-Lindau syndrome. The immunoprofile of this case suggests that hemangioblastomas are mesenchymal neoplasms exhibiting both neural and myofibroblastic differentiation.

Angiogenic histogenesis of stromal cells in hemangioblastoma: ultrastructural and immunohistochemical study

Controversy regarding the origin of characteristic stromal cells (SC) is responsible for the placement of hemangioblastoma as a single entity in the category of "tumors of uncertain histogenesis" in the current WHO classification of brain tumors. This subclassification of hemangioblastoma is, to a large extent, a consequence of a remarkable antigenic heterogeneity of SC demonstrated in many, often contradictory immunohistochemical studies. In contrast, most of the electron microscopic studies demonstrated a number of features indicating angiogenic nature of SC and, therefore, hemangioblastoma. This study reevaluated the histogenesis of SC, applying immunohistochemistry as well as electron microscopy and immunoelectron microscopy. Immunohistochemical studies confirmed most of the previous results indicating a very frequent expression of vimentin, S-100 protein, neuron-specific enolase, and cytokeratins. SC were less commonly immunoreactive for desmin, factor XIIIa, and Ricinus communis lectin receptors, and only occasionally for factor VIII and Ulex europeus lectin. They were negative for other markers of endothelial, neuronal, glial, neuroendocrine, and smooth muscle differentiation. Approximately 1% of SC showed Ki67 immunoreactivity, indicating their slight proliferative activity, consistent with the benign nature of the tumor. In contrast to the inconclusive results of the immunohistochemistry, electron microscopy demonstrated a clear relationship of SC to endothelial cells, smooth muscle cells, and pericytes. Occasional SC were found within the vascular lumina. SC often showed intracellular caveolae consistent with the formation of early capillary lumina. Moreover, occasional SC contained small Weibel-Palade bodies positive for factor VIII in immunoelectron microscopy. SC represent a heterogeneous population of abnormally differentiating mesenchymal cells of angiogenic lineage, with some morphological features of endothelium, pericytes, and smooth muscle cells. Occurrence of SC in hemangioblastoma could be related to a limited ability of angioformative stromal cells to develop an architecture of capillary lumina integrated with the vascular network of the tumor. Hemangioblastoma should be reclassified and included together with other vascular tumors of the central nervous system.

Fibrohistiocytic differentiation in capillary hemangioblastoma

Seven cases of capillary hemangioblastoma from the cerebellum and spinal cord were studied by immunohistochemical methods to determine the origin of the stromal cells. A subpopulation of factor XIIIa-positive tumor cells was a constant feature in hemangioblastomas. These stellate or spindle-shaped cells transformed into typical vacuolated stromal cells. Factor VIII-related antigen was limited to the vascular endothelium. Glial fibrillary acidic protein was present only in entrapped astrocytes. Staining for alpha-1-antitrypsin (alpha 1AT) and alpha-1-antichymotrypsin (alpha 1 ACT) was occasionally observed in stromal cells. It was concluded that the factor XIIIa-positive stromal cells in capillary hemangioblastoma indicate fibrohistiocytic differentiation, which is part of the differentiation spectrum of hemangiopericytomas.

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.

Retinal hemangioblastoma. A histologic, immunohistochemical, and ultrastructural evaluation

The authors evaluated the histologic, immunohistochemical, and ultrastructural characteristics of two eyes with retinal hemangioblastoma from patients with von Hippel-Lindau and von Hippel disease. Results of histologic evaluation showed the eyes to have degenerative changes and residual retinal hemangioblastoma. Immunohistochemical stains performed for MAC-387, factor XIIIa, lysozyme, alpha 1 anti-chymotrypsin (histiocyte markers), factor VIII-associated antigen, ulex europeaus (endothelial markers), neuron-specific enolase, chromogranin, neurofilament (neuroectodermal/neural/neuroendocrine markers) and glial fibrillary acid protein (glial marker) showed normal retinal vascular endothelium, neurons, and glial cells to stain where expected. Vascular endothelium in the retinal hemangioblastomas stained for factor VIII and ulex europeaus. Interstitial cells in the stroma of the tumors failed to stain for the histiocyte markers, chromogranin, and neurofilament. The stromal cells stained for glial fibrillary acid protein and neuron specific enolase. Ultrastructural findings in both eyes included endothelial/pericyte-lined vascular channels, elongated stromal cells, and plump, vacuolated stromal cells with ultrastructural features consistent with glial cells. This study supports the concept that retinal hemangioblastoma is composed of a proliferation of capillaries and glial cells.

Glial fibrillary acidic protein immunoreactivity of chondrocytes in immature and mature teratomas

The immunoreactivity of chondrocytes for glial fibrillary acidic protein (GFAP), other intermediate filament proteins and S-100 protein was studied in formalin-fixed paraffin-embedded sections. A total of 95 cartilage specimens were examined from five immature teratomas, 12 mature teratomas, and a teratocarcinoma. GFAP-immunoreactive chondrocytes were abundant in immature cartilages, and as the cartilages maturated, these chondrocytes decreased and became distributed peripherally. Elastic cartilage had more GFAP-immunoreactive chondrocytes than non-elastic cartilage. GFAP-immunoreactive cartilage was often located close to central nervous tissue. Immunostaining for vimentin and S-100 protein revealed extensive distribution of immunoreactive chondrocytes in immature and mature cartilages, but in mature cartilage, chondrocytes at the center had less vimentin immunoreactivity. GFAP-immunoreactive chondrocytes also showed apparent immunostaining for vimentin. There was no difference in immunohistochemical staining for the alpha and beta subunits of S-100 protein. The immunoreactivities of teratoma cartilage specimens were quite similar to those of respiratory tract cartilage.

Use of immunohistochemical methods in the differential diagnosis between primary cerebellar haemangioblastoma and metastatic renal carcinoma

The potential role of immunohistochemistry in making the distinction between primary cerebellar haemangioblastoma and metastatic renal carcinoma was investigated by examining the reaction pattern of 10 cerebellar haemangioblastomas (seven women, three men, aged 20-40 years) and 10 primary renal carcinomas (six men, four women, aged 49-82 years) to a panel of epithelial, glial, and neural/neuroendocrine antisera. The tumour cell membranes of the renal carcinomas stained strongly with epithelial membrane antigen (EMA); membrane staining was totally absent in the haemangioblastomas. Strong neurone specific enolase (NSE) and S100 staining were also seen in haemangioblastomas but were more variable than EMA staining in renal carcinomas. It is concluded that a panel of antisera is required to distinguish between histologically similar areas in primary haemangioblastomas and metastatic renal carcinomas, and that while complementing conventional histological techniques, new problems of interpretation result which must be taken into account.

Stromal cells in cerebellar haemangioblastomas: an immunocytochemical study

The nature of the stromal cells in formalin-fixed paraffin-embedded material from 23 cerebellar haemangioblastomas was investigated using antisera to intermediate filaments (glial fibrillary acidic protein, vimentin and desmin), histiocytic markers (alpha 1-antitrypsin, alpha 1-antichymotrypsin and lysozyme), glycolytic enzymes (alpha and gamma enolase and aldolase C4) and the endothelial markers, factor VIII related antigen and Ulex europaeus I lectin. Most stromal cells stained positively for vimentin and the glycolytic enzymes. Occasional process-bearing cells within the stroma stained strongly for glial fibrillary acidic protein, alpha 1-antitrypsin and alpha 1-antichymotrypsin. No stromal cell staining for desmin, lysozyme or the endothelial markers was observed, although the latter stained the vascular endothelium within all neoplasms. The findings do not support previous suggestions of an endothelial or histiocytic origin for the stromal cells. They appear to be a heterogeneous population including entrapped reactive astrocytes and locally-derived non-angiogenic cells of neuroectodermal (pial) origin.

Haemangioblastoma. An immunohistochemical study of ten cases

Ten cases of cerebellar haemangioblastoma were studied using the immunoperoxidase technique for glial fibrillary acidic protein (GFAP), Factor VIII-related antigen (F8RA), Ulex europeus agglutinin 1 (UEA-1), S-100 protein, neurone-specific enolase (NSE), leucocyte common antigen, synaptophysin, chromogranin and eight polypeptide hormones (bombesin, pancreatic polypeptide, somatostatin, thyroglobulin, calcitonin, glucagon, insulin and gastrin). GFAP and S-100 were demonstrated at the periphery of all tumours and in small groups of cells in the centre of four cases. Most of these cells had the morphology of reactive astrocytes but some had the appearance of stromal cells. In general stromal cells gave negative results. F8RA and UEA-1 stained the endothelial cells in each case but there was no stromal cell reactivity. NSE was present in the stromal cell component of all tumours. There was no staining for synaptophysin, for chromogranin, or any of the polypeptide hormones. It therefore appears that some haemangioblastomas contain an admixed non-neoplastic astrocytic element. NSE, F8RA and UEA-1 staining demonstrates that the endothelial and stromal cell parts of the tumour are antigenically distinct. Recent reports of polypeptide hormone expression cannot be confirmed and it is therefore unlikely that stromal cells originate from primitive peptidergic neurones.

Immunoperoxidase labelled antibody staining in differential diagnosis of central nervous system haemangioblastomas and central nervous system metastases of renal carcinomas

The problem of the differential diagnosis both of central nervous system haemangioblastomas and metastases of renal clear cell carcinomas was investigated by immunoperoxidase labelled antibody staining of five cases each of haemangioblastoma and metastatic renal carcinoma. Staining using anticarcinoembryonic antigen (CEA), antikeratin, antifactor VIII related antigen, and antibrush border was unhelpful. All five of the haemangioblastomas were negative and all five of the metastases were positive for epithelial membrane antigen (EMA), as defined by immunoperoxidase staining. This shows that commercially available anti-EMA monoclonal antibody is useful in distinguishing the two pathological entities.

Multifocal spinal angiosarcoma after chordotomy

A male aged 60 is reported who, 5 years after chordotomy at the Th 2/3 level, developed acute paraplegia of the legs and a sensory transverse lesion due to an extradural tumour of the Th 1-4 level. Neuropathology revealed transverse necrosis of the thoracic spinal cord (Th 1-4) due to an intradural tumour at the upper thoracic and lumbar spinal levels, the thoracic malignancy arising at the site of the previous chordotomy, with a suture being observed within the tumour mass. Histology, positive immunostaining of tumour cells with Factor VIII antigen, a specific marker of endothelial cells and the ultrastructural demonstration of Weibel-Palade bodies in endothelial cells of the tumour vessels suggested a malignant mesenchymal tumour of angiosarcoma type presumably arising from the spinal meninges, and broadly invading the spinal cord. The usual relation of this extremely rare intraspinal vasoformative malignancy to previous chordotomy is discussed.

Central neural antigens: detection and diagnostic application

During the last few years, methods have been developed which permit practical use of biochemical research on the nervous system. In the central nervous system, proteins have been identified for astrocytes (glial fibrillary acidic protein and vimentin) and oligodendroglia (myelin basic protein and other glycoproteins). For certain classes of nerve cells, the neurofilament proteins and neuron-specific enolase (a glycolytic isoenzyme) have been identified. Detection of some of these substances in body fluids is possible via radioimmunoassays (RIA) and in tissue sections using the peroxidase-antiperoxidase immunohistochemical method.

Assessing the specificity of anti-canine-factor VIII-related antigen

Antibodies to canine factor VIII-related antigen should be monospecific to accurately study this protein's location in tissue and its structure. Because no uniformly accepted standard for monospecificity exists for anti-factor VIII-related antigen, we have compared the sensitivities of three common evaluation techniques--immunodiffusion, immunoelectrophoresis, and crossed immunoelectrophoresis. Unabsorbed rabbit anti-canine factor VIII-related antigen appeared monospecific against whole plasma by all three methods; however, multiple specificities were recognized against a plasma cryoconcentrate. These results demonstrate the insensitivity of the techniques under certain conditions, which can lead to erroneous interpretation of data.