Cellular angiofibromas are benign densely vascularized fibroblastic neoplasms usually found in the lower genital tract specifically the vulva, vagina or perineum in women and the scrotum or groin in men.
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Epidemiology
Cellular angiofibromas are rare tumors found in the adult population. There is no gender predominance. The tumors show a peak incidence in the 5th decade of life in women, whereas men are usually affected in the 7th decade 1-3.
Diagnosis
The diagnosis of cellular angiofibroma is established histologically, the location of the tumor is an important clue 1.
Diagnostic criteria
Diagnostic criteria according to the WHO classification of tumors: soft tissue and bone (5th edition) 1:
- bland spindle cells in a stroma containing short bundles of wispy collagen
- many small to medium-sized thick-walled blood vessels
The following criteria are desirable:
- vulvovaginal location in women, inguinal or scrotal region in men
- RB1 deletion
Clinical presentation
Usually, the tumor manifests as a slowly progressive well-defined indolent mass 1.
Associations
In men, cellular angiofibromas can be associated with hydrocele testis or inguinal hernias 1.
Pathology
Cellular angiofibromas are richly vascularized cellular fibroblastic tumors consisting of multiple thick-walled vessels usually arising in the vulvovaginal or inguinal and scrotal regions 1-4.
Etiology
The etiology of cellular angiofibroma is unknown 1.
Location
Cellular angiofibromas are typically found in the superficial soft tissues of the genital region namely the vulvovaginal area in women and the paratesticular and inguinal areas in men, with rare examples in other body locations 1-6.
Macroscopic appearance
The gross appearance of cellular angiofibromas is that of a well-defined round to oval or lobulated tumor with a grey-pinkish to brown-yellowish color and a solid soft to rubbery consistency 1-3.
Microscopic appearance
Microscopically cellular angiofibromas show the following features 1-3:
- moderately to highly cellular tumor with an unorganized random or short fascicular pattern
- small uniform short spindle-shaped cells with pale eosinophilic cytoplasm and ill-defined borders
- edematous fibrous stroma containing short wispy collagen bundles and with focal myxoid changes or hyalinized background in a part of the cases
- prominent small to medium-sized thick-walled vessels with intramural hyaline fibrosis
- no necrosis
- no atypical mitotic activity
Immunophenotype
Immunohistochemistry stains express estrogen receptor, progesterone receptor in many cases and CD34 in about 30-60%. A minority of cases show variable expressions of desmin and smooth muscle actin (SMA) 1.
Genetics
Cellular angiofibromas frequently feature a deletion of the RB1 gene on chromosome 13q14 1.
Radiographic features
Cellular angiofibromas are well-defined highly vascularized lesions in the genital region 4.
Ultrasound
Ultrasound findings have been described as well-marginated with hypoechoic or heterogeneous architecture 5.
CT
Cellular angiofibromas have been reported as heterogeneously enhancing soft tissue mass after contrast administration 4,7.
MRI
Cellular angiofibromas have been described to appear as solid well-circumscribed variably heterogeneous soft tissue lesions 4-6.
Signal characteristics
- T1: low to intermediate signal intensity
- T2: heterogeneous intermediate to high signal intensity
- T2FS/STIR: intermediate to high signal intensity
- T1 C+ (Gd): avid heterogeneous enhancement
Radiology report
The radiological report should include a description of the following:
- location and size of the tumor
- relation to other organs
- relation to soft tissue structures structures
Treatment and prognosis
Cellular angiofibromas are benign tumors and the diagnosis is often established after excision. Local recurrences are very infrequent. Sarcomatous transformation or cell atypia exists but there are apparently no known cases, where this has changed prognosis or led to recurrence 1.
History and etymology
Cellular angiofibroma was first described by the American pathologist Marisa R Nucci and colleagues in 1997 8.
Differential diagnosis
The differential diagnosis of cellular angiofibroma includes the following tumors 1-4:
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