Pathology of Cellular Angiofibroma
|Cellular angiofibroma is a
recently described histologically distinctive benign mesenchymal neoplasm
composed of two main components, the cellular spindle cell component and
prominent stromal blood vessels.
Local excision with negative margins appears to be adequate treatment for these lesions.
Age: The tumour occurs in adult life (40-60yrs).
Site: Most common sites are the vulvovaginal region and the inguinoscrotal region. Cases in vulva are often mistaken for a Bartholin gland cyst.
Similar lesions in males have sometimes been called angiomyofibroblastoma-like tumour.
This tumour rarely occurs in retroperitoneum, perineum and subcutaneous tissues of the chest.
Macroscopic appearances: Soft or rubbery tumour with a greyish- white cut surface. Lesions in the vulva are characterized by its generally small size (less than 30mm) and usually well circumscribed margin. Examples in men tend to be larger and less clearly marginated.
A well circumscribed lesion but is usually not encapsulated.Focal extension into soft tissue can be seen.
This is a cellular tumour and is composed of small spindle cells arranged in short fascicles together with wispy collagen bundles and relatively abundant small- or medium-sized rounded vessels.
Many blood vessels with thick hyalinized walls may be present.
The spindle cells have bland oval to fusiform nuclei, pale eosinophilic cytoplasm and indistinct margins.
There may be prominent mitotic activity (up to 11 per 10 HPF). Abnormal mitoses are absent. Usually there is no cellular atypia or necrosis.
Focal areas of marked cellular atypia reminiscent of symplastic change within a uterine leiomyoma has been reported in one case.
Lobules of adipocytes may be identified at the periphery.
Other features include presence of stromal mast cells and occasional small collections of mature lymphocytes.
Immunohistochemistry: Tumour cells express vimentin, CD99, and both estrogen and progesterone receptors.
The cells sometimes show positivty for CD34.
The cells are negative for S100 protein, smooth muscle actin, desmin, epithelial membrane antigen and cytokeratin.
Aggressive angiomyxoma (deeply located, less cellular, abundant myxoid matrix, more infiltrative) ;
Angiomyofibroblastoma (less cellular, medium sized thickened hyalinized vessels are not present, composed of rather rounded myoid tumour cells which stain positively for desmin) ;
Spindle cell lipoma (more common in male patients , usually located the neck and upper back , contains ropey refractile collagen bundles, lacks numerous blood vessels and hyalinized blood vessels, tumour cels are consistently positive for CD34) ;
Perineurioma (arranged in a whorled pattern, lacks thick-walled vessels and is positive for EMA) ;
Leiomyoma (Piloleiomyoma; Angioleiomyoma; Lipoleiomyoma; Genital Leiomyoma) ; (features of smooth muscle differentiation- intersecting fascicles of spindle cells with blunt ended nuclei and eosinophilic cytoplasm, stain positively for myogenic markers)
Leiomyosarcoma (Cellular angiofibroma may be mistaken for sarcoma because of brisk mitotic activity) ;
Solitary fibrous tumour (Hemangiopericytoma-like vascular pattern, stromal keloidal- type hyalinization);Fibroepithelial stromal polyp ; Glomangiopericytoma ; Mammary-type myofibroblastoma.
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