Pathology of Giant Cell Angiofibroma - Infographic
Giant cell angiofibroma was introduced as an entity by Dei Tos et al. in 1995.
It is a rare mesenchymal neoplasm most commonly arising in the soft tissues near the orbit.
Age Middle-aged patients.
Site: Orbit or eyelid and in extraorbital sites.
Extraorbital sites include- head and neck region (may occur in the nasolacrimal duct and lacrimal sac region), back, axilla, hip, vulva, inguinal region, mediastinum and retroperitoneum.
In males this lesion is common in the orbit and in females it usually occurs in the extraorbital sites.
Well circumscribed lesion which may be encapsulated.
Cut surface has a greyish white appearance.
In some cases the cut surface may have a lymphangioma-like cystic appearance.
Histologically, the tumour is composed of a mixture of cytologically bland spindle-shaped cells and ovoid cells of varying cellularity.
The spindled tumour cells have large, rounded nuclei, sometimes with complex folded shape and pseudoinclusions.
The cells are set in a variably collagenous and myxoid stroma.
There are prominent, various-sized blood vessels, often with perivascular hyalinization.
Pseudovascular angiectoid spaces are present filled with an amorphous eosinophilic material.
These are partly lined by multi- or mononuclear giant cells.
Rare multinucleated floret-like giant cells are seen.
Other features: Keloidal collagen deposition ; staghorn pericytomatous vascular spaces, similar to those seen in solitary fibrous tumour, clusters of adipocytes- resembling lipomatous hemangiopericytoma ; presence of mitotic figures (ranged from 1 to 3 mitoses/10 high-power fields).
Immunohistochemically, the mononuclear and multinucleated cells within these tumours are positive for CD34. CD99 is positive, bcl-2 is variably positive.
Tumour cells are also negative for other antigens, including Factor VIII-related antigen, desmin, alpha smooth muscle actin, myoglobin, S-100 protein, LeuM1, lysozyme, alpha-1-antitrypsin and cytokeratins (AE1/AE3 and CAM5.2).
Cytogenetics: In a case of giant cell angiofibroma, abnormalities of chromosome 6 with a common pattern involving 6q13 were detected.
Orbital lesion- Solitary fibrous tumour
Extra-orbital lesion- Giant cell fibroblastoma ; Deep fibrous histiocytoma ; Synovial sarcoma ; Schwannoma ; Haemangiopericytoma ; Fibrosarcoma ; Other tumours containing osteoclast like giant cells ( In GCA - CD68 is negative).
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