Cellular angiofibroma

Definition

A rare benign tumour occurring usually in the vulva and in the male inguinoscrotal region, composed of a highly cellular stroma and highly vascular. The tumour in the male scrotum have been termed angiomyofibroblastoma-like tumour.

Clinical features

The tumour occurs throughout adult life, with mean ages of 46 years in women, 61 years in men⁹. Subcutaneous tumours are more common than those in the dermis. As well as the superficial soft tissues of the vulval and the male inguinoscrotal region⁴, this tumour rarely occurs in retroperitoneum, perineum⁵ and subcutaneous tissues of the chest⁸. It has its peak incidence in the fifth to seventh decades of life. The clinical diagnosis is often of a Bartholin's gland cyst⁵.

Macroscopic appearances

The tumour is well circumscribed, soft or rubbery with a grey-pink to yellow-brown cut surface.

Histopathology

The presence of a fibrous pseudocapsule is variable. The tumour is generally well circumscribed, but may show focal infiltration⁵. There are bland short spindle cells with scanty cytoplasm and ill-defined borders, forming ill-defined fascicles. Rarely, the cells may be epithelioid. There may be brisk mitotic activity (up to 11 per 10 HPF) but atypical mitoses and necrosis are absent. There is a uniform distribution of small to medium size vessels with perivascular hyalinised fibrosis. Multiple lumina suggest recanalisation in some case.⁵ Up to 50% of cases show small clusters, rarely larger lobules, of adipocytes, usually peripherally. A moderate lymphocytic infiltrate is seen throughout the stroma, sometimes with perivascular lymphoid aggregates.

The stroma usually consists of fine collage; there may be some thick collagen bundles, oedema or myxoid⁵ change. Males tend to show degenerative changes, consisting of intravascular thrombi, erythrocyte extravasation, haemosiderin deposition and pseudoangiomatoid cyst formation.

One case has been reported with a focus of pleomorphic liposarcoma⁹.

Immunohistochemistry

	Vimentin	strongly positive0, 1/11, 1/13, 7/7 (male cases)4, 4/45, 1/18
	CD34:	positive in one third of cases0, 0/11, 1/13, 4/8 (male cases)4, 2/65, 0/18, 29/489
	SMA	negative in females, variable in males0, 0/11, 2/8 (male cases)4, 0/45, 10/489
	Muscle-specific actin	negative in females, variable in males0, 3/8 (male cases)4, 0/45
	Desmin	negative in females, variable in males0, 0/11, 0/13, 3/8 (male cases)4, 0/45, 4/489
	S-100	0/11, 0/13, negative 4, 0/45, 0/489
	EMA	0/11, 0/45
	Cytokeratin	0/11, 0/45
	oestrogen receptors	1/13, 3/7 (male cases)4, 7/249
	progesterone receptors	1/13, 5/7 (male cases)4, 11/249

Ultrastructure

Cells are fibroblastic or myofibroblastic.

Differential diagnosis

• Aggressive angiomyxoma: is paucicellular with stellate cells in a myxoid stroma. Margins are infiltrating. It also contains small to medium size vessels, often with hyalinised walls. Small clusters of smooth muscle cells extend from blood vessels. Desmin is positive.

• Angiomyofibroblastoma: there is perivascular cellular crowding. Vessels are relatively small. Desmin is positive.

• Glomangiopericytoma

• Spindle cell lipoma: has not been described in the vulva, although it has in the male groin⁶. Both cases occur in the neck, shoulder or back, showing sparse mature adipocytes and bland spindle cells. Cellular angiofibroma has more numerous vessels, with hyalinised walls. Spindle cell lipoma has more ropey collagen, blood vessels are inconspicuous: it is also positive for CD34.

• Mammary-type myofibroblastoma: may rarely occur in the male inguinal region. Vessels are inconspicuous. There is coexpression of desmin and CD34.

• Fibroepithelial stromal polyp if superficial. Cells show heterogeneity not seen in cellular angiofibroma. The stromal cells are positive for desmin.

• Angiomyxolipoma: contains more adipose tissue and is much less cellular⁵.

• Solitary fibrous tumour: has a "patternless" architecture, keloid hyalinisation and is strongly positive for CD34.

• Perineuroma:: both show short fascicles of fusiform cells. Perineuroma shows a lamellar or whorled pattern but lacks hyalinised blood vessels. Perineuroma is positive for EMA.

• Leiomyoma: cells have abundant eosinophilic cytoplasm and cigar-shaped nuclei. Actin and desmin are positive.

Management

Local resection is adequate, with only occasional local recurrence⁴.

Prognosis

The tumour is benign.

References

⁰World Health Organization Classification of Tumours, Tumours of Soft Tissues and Bone, IARC Press 2002.

¹Colombat, M., M. E. Liard-Meillon, et al. (2001). "[Cellular angiofibroma. A rare vulvar tumor. Report of a case]." Ann Pathol 21(2): 145-8.

²Curry, J. L., J. L. Olejnik, et al. (2001). "Cellular angiofibroma of the vulva with DNA ploidy analysis." Int J Gynecol Pathol 20(2): 200-3.

³Lane, J. E., A. N. Walker, et al. (2001). "Cellular angiofibroma of the vulva." Gynecol Oncol 81(2): 326-9.

⁴Laskin, W. B., J. F. Fetsch, et al. (1998). "Angiomyofibroblastomalike tumor of the male genital tract: analysis of 11 cases with comparison to female angiomyofibroblastoma and spindle cell lipoma." Am J Surg Pathol 22(1): 6-16.

⁵Nucci, M. R., S. R. Granter, et al. (1997). "Cellular angiofibroma: a benign neoplasm distinct from angiomyofibroblastoma and spindle cell lipoma." Am J Surg Pathol 21(6): 636-44.

⁶Beham, A., C. Schmid, et al. (1989). "Spindle cell and pleomorphic lipoma: an immunohistochemical study and histogenetic analysis." J Pathol 158(3): 219-22.

⁷Nucci, M. R. and C. D. Fletcher (2000). "Vulvovaginal soft tissue tumours: update and review." Histopathology 36(2): 97-108.

⁸Garijo, M. F. and J. F. Val-Bernal (1998). "Extravulvar subcutaneous cellular angiofibroma." J Cutan Pathol 25(6): 327-32.

⁹Iwasa, Y. and C. D. Fletcher (2004). "Cellular angiofibroma: clinicopathologic and immunohistochemical analysis of 51 cases." Am J Surg Pathol 28(11): 1426-35.

This page last revised 29.12.2004.

©SMUHT/PW Bishop