Nasopharyngeal angiofibroma

L.D.R. Thompson J.C. Fanburg-Smith

Angiofibroma Nasal
Fig. 2.27 Nasopharyngeal angiofibroma. The intact respiratory epithelium overlies a richly vascular neoplasm which has variably-sized vessels surrounded by a cellular fibroblastic stroma with collagen.

The spectrum and clinicopathological features of nasopharyngeal soft tissue tumours are similar to those of other sites in the upper aerodigestive tract, except for angiofibroma, which typically presents in the nasopharynx.

Definition

A benign, highly cellular and richly vascularized mesenchymal neoplasm that involves the nasopharynx in males.

ICD-O code 9160/0

Synonyms

Juvenile nasopharyngeal angiofibroma; angiofibroma; fibroangioma; fibroma

Epidemiology

Nasopharyngeal angiofibroma represents <1% of all nasopharyngeal tumours {190,267,512,1434,1503,1861, 2654}. Boys and adolescent to young men are almost exclusively affected, with a peak in the 2nd decade of life. If a female is affected, testicular feminisation has to be excluded. Fair-skinned and red-haired males are more commonly affected.

Etiology

There is no known etiology although testosterone-dependent puberty-induced tumour growth may be ameliorated by blockade of estrogen or progesterone receptors within the tumour {717, 1861}.

Localization

This tumour arises in the posterolateral nasal wall or the nasopharynx. There is often extensive infiltration into the surrounding tissues {190,267,512,1434, 1503,1861,2654}.

Clinical features

Patients usually present with nasal obstruction and/or recurrent, spontaneous epistaxis, nasal discharge, facial deformity (including proptosis), diplopia, exophthalmos, sinusitis, otitis media, tinnitus, rhinolalia, deafness, headaches, dyspnoea, and rarely, anosmia or pain {190,267,512,1434,1503,1861,2654}.

Imaging

Routine radiographs reveal a soft tissue density in the nasopharynx in conjunction with anterior bowing of the posterior wall of the maxillary sinus as well as distortion and posterior displacement of the pterygoid plates (Holman-Miller sign). Bony margins may be eroded, but are distinct. Computed tomography allows for accurate determination of the extent of the disease as well as the best possible surgical approach. Angiography allows for identification of the feeding vessel(s) and pre-surgical embolization. Tumour blush on angiogram is characteristic {1434,2654}. Due precautions have to be taken in obtaining biopsies from the lesion because of the risk of life-threatening bleeding.

Macroscopy

The tumours range in size up to 22 cm, with a mean of about 4 cm. They are polypoid with a rounded or multinodular contour, with red, grey-tan cut surfaces

{190,267,512,1434,1503,1861,2654}.

Tumour spread and staging

The tumour expands in all directions from the nasopharyngeal region, following the path of least resistance: anteriorly into the nasal cavity and maxillary sinuses, laterally into the pterygoid region, temporal fossa and infratemporal fossa (resulting in a cheek or intraoral buccal mass); superiorly into orbit and middle cranial fossa; or to the opposite side. This type of extensive involvement is seen in up to 30% of cases, explaining the potential aggressive nature of this benign neoplasm {190,267,512,1434,1503,1861, 2654}.

A number of staging systems have been suggested, {384,767,2111,2309} with a modification based on size and location used most frequently.

Histopathology

There is a vascular proliferation set in a fibrous stroma. The vessels are mostly thin-walled, slit-like ("staghorn") or dilated with calibres ranging from capillary size to large, patulous vessels. The mus cular layer can be absent, focal and padlike, or circumferential. Endothelial cells may be plump but are usually attenuated. The fibrous stroma consists of plump spindle, round, angular, or stellate shaped cells and a varying amount of fine and coarse collagen fibres; background myxoid degeneration is common (especially in embolized specimens). The nuclei of the stromal cells are generally cytologically bland, but they may be multinucleated or show some degree of pleomorphism in the more cellular areas. Mast cells may be seen, but other inflammatory elements are usually absent (except when there is surface ulceration) {190,267,512,1434,1503,1861,2654}. Long-standing lesions show increased fibrosis and diminished vasculature. Treatment with hormones results in increased collagenization of the stroma with fewer, but thicker-walled vessels. In specimens excised after embolization, the tumour often shows areas of infarction, and emboli can be seen in some blood vessels. Sarcomatous transformation is an exceedingly uncommon event, usually following radiation therapy {2431}.

Immunoprofile

Occasional elastic fibres can be identified in the vessel walls, although they are generally absent in the stroma. The vessel wall cells are immunoreactive with vimentin and smooth muscle actin (SMA), whereas the stromal cells are immunoreactive with vimentin only, except in areas of increased fibrosis, where focal SMA may be identified. Desmin may be focally immunoreactive in larger vessels at the periphery of the tumour. Stromal and endothelial cells are variably reactive with androgen and estrogen/progesterone receptors. Factor VIII R-Ag, CD34 and CD31 highlight the endothelium, but not the stromal cells. The stromal cells are negative for S-100 protein {190,1503}. Platelet derived growth factor B and insulin-like growth factor type II are both over-expressed {1812}.

Electron microscopy

Ultrastructurally, the stromal cells contain lobulated nuclei, intranuclear inclusions, variable amounts of rough endoplasmic reticulum and thin filaments, hemidesmo-somes, focal basal lamina and prominent pinocytotic vesicles, suggesting a hybrid mesenchymal cell (myofibroblast) {2565}.

Differential diagnosis

The differential diagnosis includes lobular capillary haemangioma (pyogenic

Table 2.05 System for staging nasopharyngeal angiofibroma {384,767,2309}.

Stage Description

Stage I Tumour limited to the nasopharynx with no bone destruction Stage II Tumour invading the nasal cavity, maxillary, ethmoid, or sphenoid sinuses with no bone destruction Stage III Tumour invading the pterygo-palatine fossa, infra-temporal fossa, orbit or parasellar region Stage IV Tumour with massive invasion of the cranial cavity, cavernous sinus, optic chiasm, or pituitary fossa granuloma), nasal inflammatory polyps with fibrosis or atypical stromal cells, antrochoanal polyps, and peripheral nerve sheath tumour.

Histogenesis

It has been proposed that the tumour arises from a fibrovascular nidus that lies dormant until puberty, when testosterone stimulates tumour growth {1861}.

Genetic susceptibility

There are isolated reports of an association with familial adenomatous polyposis {757,885}.

Prognosis and predictive factors

This benign tumour is characterized by local aggressive growth, with recurrences in about 20% of patients (>50% in older series), most commonly intracra-nially, and usually within the first 2 years after diagnosis. Patients may be managed with selective angiographic embolization or hormonal therapy prior to definitive surgical resection. Radiation therapy has been successfully implemented to manage large, intracranial, or recurrent tumours, but surgery is still the therapy of choice {190,267,512,1434, 1503,1861,2654}.

^ti "¡» U i -f ■ . tM 1 ■■■ 'l -1_ * fi" - . CMm h

■ -,i V " m" J ■ 1 *' ' "V".

■A WÊÊm

. ■ 'if.'. ? -B

D ■ ■ -SBH^BËTïâ,

Fig. 2.28 Nasopharyngeal angiofibroma. A Thin walled vessels surrounded by dense, "keloid-like" collagen. Stellate fibroblasts are noted. B Smooth muscle-walled vessels, patulous vessels and capillaries are all surrounded by the characteristic collagenized stroma. C A large thin-walled vessel is associated with fibrous connective tissue, inflammatory cells and stellate fibroblasts. D Heavily collagenized stroma demonstrates only a few stellate fibroblastic cells.

Fig. 2.28 Nasopharyngeal angiofibroma. A Thin walled vessels surrounded by dense, "keloid-like" collagen. Stellate fibroblasts are noted. B Smooth muscle-walled vessels, patulous vessels and capillaries are all surrounded by the characteristic collagenized stroma. C A large thin-walled vessel is associated with fibrous connective tissue, inflammatory cells and stellate fibroblasts. D Heavily collagenized stroma demonstrates only a few stellate fibroblastic cells.

Was this article helpful?

+2 0
Peripheral Neuropathy Natural Treatment Options

Peripheral Neuropathy Natural Treatment Options

This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.

Get My Free Ebook


Post a comment