Cytokeratin expression in epithelioid vascular neoplasms.

Seven epithelioid and eight non-epithelioid vascular tumors were studied by the avidin-biotin-peroxidase method for the presence of endothelial- and epithelial-associated markers, using Ulex europaeus agglutinin-1 (UEA-1) lectin, and antibodies directed against factor VIII-related antigen, (FVIII-RA), vimentin, keratin, carcinoembryonic antigen, and epithelial membrane antigen. The cases included four epithelioid hemangiomas, two epithelioid hemangioendotheliomas (EHE), one epithelioid angiosarcoma (EAS), four common non-epithelioid capillary hemangiomas, and four non-epithelioid angiosarcomas. Staining for FVIII-RA, UEA-1, and vimentin were observed in all cases. The EAS showed staining for keratin in formalin-fixed, paraffin-embedded sections and in frozen sections. Staining for keratin was also observed in frozen sections of one EHE. Both keratin-positive vascular tumors were confirmed with electron microscopy. Carcinoembryonic antigen and epithelial membrane antigen stains were negative in all cases. Our results show that the epithelioid vascular tumors EHE and EAS, in addition to staining for the endothelial markers and vimentin, may also express the epithelial marker keratin. This is important since these tumors may closely resemble carcinomas by routine light microscopy. This study further underscores the importance of using a broad panel of immunohistochemical markers in the diagnostic workup of soft-tissue neoplasms.

Antibodies to intermediate filament proteins. The differential diagnosis of cutaneous tumors.

One hundred cutaneous tumors were investigated immunohistopathologically for the expression of intermediate filament (IF) proteins. Epithelial tumors, such as basocellular and squamous cell carcinomas, cutaneous adnexal tumors, and metastatic carcinomas showed keratin positivity in a varying number of tumor cells with two keratin antibodies with different specificities. Neoplastic cells of fibrohistiocytic tumors, pigmented nevi, melanomas, hemangiomas, glomus tumors, and lymphomas were positive for vimentin, but not for keratin or desmin. Cutaneous leiomyomas and leiomyosarcomas, on the other hand, were positive for desmin. The results show that the typing of IFs enables the differential diagnosis between carcinomas and sarcomas or melanomas, epidermal appendage tumors, and mesenchymal tumors, and between fibrohistiocytic and leiomyocytic tumors, and therefore are of diagnostic value in histopathologic problems of the skin.

Determination of glial fibrillary acidic protein (GFAP) in human brain tumors.

Brain tumors have been tested for their glial fibrillary acidic protein (GFAP) content by means of the rocket electrophoresis technique. Meningiomas and neurinomas were low in GFAP. Metastases had a low level of GFAP except when contaminated with surrounding tissue. Non-nervous tumors such as myeloma, myeloplaxoma and adenocarcinoma gave negative results. More detailed correlations with histological observations have been looked for in glial tumors. Low levels of GFAP were always associated with signs of malignancy such as mitoses and giant or atypical cells, whereas high levels of GFAP were correlated with the presence of well-preserved astrocytes.

[DNA cytofluorometry of soft tissue tumors].

We carried out DNA cytofluorometry with propidium iodide stain on the 17 cases of soft tissue tumors including giant cell tumor of the tendon sheath, pigmented villonodular synovitis, 2 hemangiomas, 3 lipomas, 5 schwannomas, 3 neurofibromas, liposarcoma and synovial sarcoma. The benign tumors were characterized by regular polyploidization with very few S-phase cells, indicating slow tumor growth. Most of the malignant soft tissue tumors were associated with remarkable polyploidization with an increase in S-phase cells. However, some malignant tumors did not show polyploidization. We concluded, therefore, that an increase in S-phase cells is an important, cytofluorometric criterion for malignancy of soft tissue tumors.

Angiomatoid malignant fibrous histiocytoma: flow cytometric DNA analysis of six cases.

Using flow cytometry, we examined the DNA content of six angiomatoid "malignant" fibrous histiocytomas (AMFH), seven nonangiomatoid MFH, and seven myxoid variants of MFH. All six AMFHs were diploid. All nonangiomatoid MFHs and six of seven of the myxoid variant were aneuploid. The clinical course, histological appearance, and ploidy pattern of AMFH are distinctly different from other MFH variants. These differences strongly suggest that AMFH is at the benign end of the clinicobiologic spectrum manifested by "malignant" fibrous histiocytomas.

Immunohistological evaluation of endothelial markers and basement membrane components in port-wine stains.

As shown by an immunohistological study, the endothelial cells in the lesions of port-wine stains (PWSs), investigated for factor VIII-related antigen and Ulex europaeus agglutinin I lectin, were found to be swollen or flattened corresponding to mild or pronounced dilatation of vessels, respectively. Furthermore, dilated vessels in the lesional skin exhibited a broader staining for type IV collagen, laminin and fibronectin, which, however, was not considered to be of primary pathogenetic importance for vessel dilatation in PWSs. As concluded from the number of vessels, no vascular proliferation occurred, which indicates that PWS is not a true hemangioma but a special clinical type of telangiectasia.

Immunohistochemical evaluation of factor VIII related antigen, filament proteins and lectin binding in haemangiomas.

Immunohistochemical identification of factor VIII related antigen (F VIII RAG) filament proteins (actin, myosin, filamin, vimentin and desmin) and lectin binding patterns of Con A, PNA, SBA, WGA, RCA-1, UEA-1 and DBA in the endothelial cells and the muscular layers of haemangiomas and normal blood vessels are reported, using paraffin sections with the HRP method. The endothelial cells of haemangiomas were usually strongly positive to F VIII RAG as were those from capillary vessels and other small vessels. Some of the endothelium from haemangiomas and angiokeratomas was negative for factor VIII. The vessel walls of hemangiomas showed staining slightly positive for microfilaments (actin, myosin, filamin). The smooth muscle layer in small vessels showed a more marked staining with actin. Vimentin and desmin reactions in the vessel walls of haemangioma and in normal vessels were slight or moderate. UEA-1 lectin binding was constantly positive in endothelial cells from hemangiomas and in blood vessels. SBA and WGA binding appeared in the border layer of endothelium in haemangiomas and normal vessels.

Tumour angiogenesis factor (TAF) in human and animal tumours.

Extracts were made from Walker 256 carcinoma, spontaneous rat mammary adenocarcinoma, Wilms' tumour, human neuroblastoma and human haemangioma. Chromatography of the extracts on Sephadex G-100 yielded four fractions, A, B, C and D. Injection of fractions B and C resulted in the growth of new capillaries in the subcutaneous fascia or rats. Controls, e.g. similar extracts of rat liver or human kidney, did not induce neovascularisation. The endothelium of newly-formed blood vessels contained many mitotic figures. A limitation of this method is that it is qualitative only. In order to develop a quantitative in vitro assay for a tumour angiogenesis factor (TAF), short-term primary cultures were initiated from adult rat brain white matter, as cells from such cultures were shown to be vascular in origin. Addition of fractions containing TAF (B and C) which were active in vivo failed to stimulate thymidine uptake by the cells. The possible reasons for this failure and the therapeutic potential of TAF in cancer control are discussed.

Factor VIII-related antigen in canine endothelial neoplasms: an immunohistochemical study.

Canine vascular tumors (47 hemangiomas, 36 hemangiosarcomas) were investigated for the endothelial cell marker factor VIII-related antigen (F VIII RAg). The primary antibody was a commercial rabbit anti-human (r/h) F VIII RAg antiserum. All (100%) hemangiomas and 32 (89%) of 36 hemangiosarcomas stained for F VIII RAg. One hemangiosarcoma (3%) was negative, and three tumors (8%) were equivocal in staining. Rarely, the interpretation of stained immature endothelial cells was difficult. The r/h F VIII RAg antibody was a positive marker of normal, reactive, and neoplastic endothelial cells in the dog.