Browsing by Author "Athanasou, N.A."

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Immunophenotypic distinction between pigmented villonodular synovitis and haemosiderotic synovitis
(BMJ Publishing Group, 2010) Mahendra, G.; Kliskey, K.; Athanasou, N.A.
AIM: Haemosiderotic synovitis (HS) is caused by excessive bleeding into a joint. It occurs secondary to a variety of conditions and needs to be distinguished from pigmented villonodular synovitis (PVNS) for the purposes of treatment. The histopathological distinction between these conditions, particularly in biopsy specimens, can be problematic. METHODS: Immunophenotypic findings in 20 cases of PVNS and 20 cases of HS were analysed using monoclonal antibodies against proliferation (Ki-67), apoptosis (bcl2), macrophage (CD14, CD68, HLA-DR) and osteoclast (CD51) antigens. RESULTS: Macrophages in PVNS and HS expressed CD14 and HLA-DR. The giant cells in PVNS, but not those in HS, expressed CD51 and were negative for CD14 and HLA-DR, indicating that these cells had an osteoclast phenotype. Considerably more CD51-expressing mononuclear cells were noted in PVNS compared with HS. The Ki-67 proliferation index was higher in PVNS than in HS. CONCLUSIONS: The findings indicate that there are immunophenotypic differences in giant cells between PVNS and HS, and that expression of CD51 and a high Ki-67 index effectively distinguishes between these two conditions
Intratumoural lymphatics in benign and malignant soft tissue tumours
(Springer International, 2008) Mahendra, G.; Kliskey, K.; Williams, K.; Hollowood, K.; Jackson, D.; Athanasou, N.A.
Soft tissue sarcomas do not generally metastasise via lymphatics, and the presence or absence of lymphatic vessels within sarcomas and benignsoft tissue tumours is not known. In this study, we determined whether lymphatic vessels were present in a wide range of benign and malignant softtissue lesions by examining intratumoural expression of the lymphatic endothelial cell markers, Lyve-1 and podoplanin. Intratumoural Lyve-1+/podoplanin+ lymphatics were not identified in sarcomas apart from all cases of epithelioid sarcoma (a tumour which is known to metastasise to lymph nodes) and a few cases of leiomyosarcoma, rhabdomyosarcoma and synovial sarcoma. Intratumoural lymphatics were also absent in mostbenign soft tissue tumours. Reparative and inflammatory soft tissue lesions contained lymphatics, as did all (pseudosarcomatous) proliferative myofibroblastic lesions including nodular, proliferative and ischaemic fasciitis, elastofibroma, nuchal fibroma and deep fibromatosis. Our results show that most soft tissue sarcomas do not contain intratumoural lymphatics, a finding which is consistent with the infrequent finding of sarcoma metastasis to lymph nodes. In contrast to fibrosarcoma and a number of other malignant spindle cell tumours, proliferative fibroblastic/myofibroblastic lesions of soft tissue contain intralesional lymphatic vessels.
Necrotic and inflammatory changes in metal-on-metal resurfacing hip arthroplasties
(Informa Healthcare, 2009) Mahendra, G.; Pandit, H.; Kliskey, K.; Murray, D.; Gill, H.S.; Athanasou, N.A.
BACKGROUND: Necrosis and inflammation in peri-implant soft tissues have been described in failed second-generation metal-on-metal (MoM) resurfacing hip arthroplasties and in the pseudotumors associated with these implants. The precise frequency and significance of these tissue changes is unknown. METHOD: We analyzed morphological and immunophenotypic changes in the periprosthetic soft tissues and femoral heads of 52 revised MoM arthroplasties (fracture in 21, pseudotumor in 13, component loosening in 9, and other causes in 9 cases).RESULTS: Substantial necrosis was observed in the periprosthetic connective tissue in 28 of the cases, including all pseudotumors, and 5 cases of component loosening. A heavy, diffuse inflammatory cell infiltrate composed mainly of HLA-DR+/CD14+/CD68+ macrophages and CD3+ T cells was seen in 45 of the cases. Perivascular lymphoid aggregates composed of CD3+ cells and CD20+ B cells were noted in 27 of the cases, but they were not seen in all cases of component loosening or pseudotumors. Plasma cells were noted in 30 cases. Macrophage granulomas were noted in 6 cases of component loosening. In the bone marrow of the femoral head, a macrophage and T cell response was seen in 31 of the cases; lymphoid aggregates were noted in 19 of the cases and discrete granulomas in 1 case. INTERPRETATION: Our findings indicate that there is a spectrum of necrotic and inflammatory changes in response to the deposition of cobalt-chrome (Co-Cr) wear particles in periprosthetic tissues. Areas of extensive coagulative necrosis and a macrophage and T lymphocyte response occur in implant failure and pseudotumors, in which there is also granuloma formation. The pathogenesis of these changes is uncertain but it may involve both a cytotoxic response and a delayed hypersensitivity (type IV) response to Co-Cr particles.
Smooth muscle actin expression in primary bone tumours
(Springer International, 2012) Hemingway, F.; Kashima, T.G.; Mahendra, G.; Dhongre, A.; Hogendoorn, P.C.W.; Mertens, F.; Athanasou, N.A.
ABSTRACT: Alpha isoform of smooth muscle actin (SMA) expression has been reported in giant cell tumour of bone (GCTB) and other benign and malignant bone tumours, but the pattern of SMA expression and the precise nature of SMA-expressing cells in these lesions is uncertain. We determined by immunohistochemistry the expression of SMA and other muscle and vascular markers in normal bone, GCTB and a wide range of primary benign and malignant bone tumours. Cultured stromal cells of GCTB, chondroblastoma (CB), and aneurysmal bone cyst (ABC) were also analysed for SMA expression. SMA was only noted in blood vessels in normal bone. SMA was expressed by mononuclear stromal cells (MSC) cultured from GCTB, ABC and CB. SMA was strongly and diffusely expressed by MSC in non-ossifying fibroma, fibrous dysplasia, and "brown tumour" of hyperparathyroidism. SMA expression was also noted in GCTB, ABC, CB, chondromyxoid fibroma, malignant fibrous histiocytoma of bone and osteosarcoma. Little or no SMA was noted in Langerhans cell histiocytosis, simple bone cyst, Ewing's sarcoma, osteoblastoma, osteoid osteoma, enchondroma, osteochondroma, chondrosarcoma, myeloma, lymphoma, chordoma and adamantinoma. Our findings show that there is differential SMA expression in primary bone tumours and that identifying the presence or absence of SMA is useful in the differential diagnosis of these lesions. The nature of SMA-expressing cells in bone tumours is uncertain but they are negative for desmin and caldesmon and could represent either myofibroblasts or perivascular cells, such as pericytes.