nasoppharyngeal angiofibroma

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nasoppharyngeal angiofibroma

Post by mohweh on Tue Mar 18, 2008 2:18 pm

Juvenile angiofibroma (JNA) is a benign tumor that tends to bleed and occurs in the nasopharynx of prepubertal and adolescent males.

History of the Procedure
Hippocrates described the tumor in the 5th century BC, but Friedberg first used the term angiofibroma in 1940. Other titles (eg, nasopharyngeal fibroma, bleeding fibroma of adolescence, fibroangioma) have also been used.

Frequency
JNA accounts for 0.05% of all head and neck tumors. A frequency of 1:5,000-1:60,000 in otolaryngology patients has been reported.

Sex
JNA occurs exclusively in males. Females with JNA should undergo genetic testing.

Age
Onset is most commonly in the second decade; range is 7-19 years. JNA is rare in patients older than 25 years.

Etiolgy
The lesion originates in close proximity to the posterior attachment of the middle turbinate, near the superior border of the sphenopalatine foramen.

A hormonal theory has been suggested because of the lesion's occurrence in adolescent males.

Other theories include a desmoplastic response of the nasopharyngeal periosteum or the embryonic fibrocartilage between the basiocciput and the basisphenoid.

Etiology from nonchromaffin paraganglionic cells of the terminal branches of the maxillary artery has also been suggested. Comparative genomic hybridization analysis of these tumors revealed deletions of chromosome 17, including regions for the tumor suppressor gene p53 as well as the Her-2/neu oncogene.

Pathophysiology
The tumor starts adjacent to the sphenopalatine foramen. Large tumors are frequently bilobed or dumbbell-shaped, with one portion of the tumor filling the nasopharynx and the other portion extending to the pterygopalatine fossa.

Anterior growth occurs under the nasopharyngeal mucous membrane, displacing it anteriorly and inferiorly toward the postnasal space. Eventually, the nasal cavity is filled on one side, and the septum deviates to the other side. Superior growth is directed toward the sphenoid sinus, which may also be eroded. The cavernous sinus may become invaded if the tumor advances further.

Lateral spread is directed toward the pterygopalatine fossa, bowing the posterior wall of the maxillary sinus. Later, the infratemporal fossa is invaded. Occasionally, the greater wing of the sphenoid may be eroded, exposing the middle fossa dura. Proptosis and optic nerve atrophy result if orbital fissures are encroached upon by the tumor.

Extranasopharyngeal angiofibroma is extremely rare and tends to occur in older patients, predominately in females, but the tumor is less vascular and less aggressive than JNA.

Clinical
Symptoms
Nasal obstruction (80-90%) - Most frequent symptom, especially in initial stages
Epistaxis (45-60%) - Mostly unilateral and recurrent; usually severe epistaxis that necessitates medical attention; diagnosis of angiofibroma in adolescent males to be ruled out
Headache (25%) - Especially if paranasal sinuses are blocked
Facial swelling (10-18%)
Other symptoms - Unilateral rhinorrhea, anosmia, hyposmia, rhinolalia, deafness, otalgia, swelling of the palate, deformity of the cheek

Signs
Nasal mass (80%)
Orbital mass (15%)
Proptosis (10-15%)

Other signs including serous otitis due to eustachian tube blockage, zygomatic swelling and trismus that denote spread of the tumor to the infratemporal fossa, decreasing vision due to optic nerve tenting (rare)

Differential diagnosis

Other causes of nasal obstruction, (eg, nasal polyps, antrochoanal polyp, teratoma, encephalocele, dermoids, inverting papilloma, rhabdomyosarcoma, squamous cell carcinoma)
Other causes of epistaxis, systemic or local
Other causes of proptosis or orbital swellings

Imaging Studies
Plain radiography
View of the sinuses may demonstrate nasopharyngeal polyp.
Bowing of the posterior wall of the maxillary sinus and maxillary sinus opacification is very suggestive of JNA.
Newer radiographic modalities have surpassed plain films in usefulness.

CT scanning
Images demonstrate extent of the tumor.
Extension to the sphenoid sinus, erosion of the greater sphenoidal wing, or invasion of the pterygomaxillary and infratemporal fossae is usually visualized.

Magnetic resonance imaging (MRI) is indicated to delineate and define the extent of the tumor , especially in cases of intracranial involvement.

Angiography shows the branches of the external carotid system to be the primary feeders (94%).
The main supply comes from the internal maxillary artery, but ascending pharyngeal or vidian arteries may contribute to the blood supply.
Unnamed branches from the internal carotid artery contribute to vascularity in rare instances.

Histologic Findings
On gross examination, the tumor is usually sessile, lobulated, rubbery, and red-pink to tan-gray in appearance. In rare cases, the tumor is polypoid or pedunculated.

Nasopharyngeal angiofibroma is usually encapsulated and composed of vascular tissue and fibrous stroma with coarse or fine collagen fibers. Vessels are thin-walled, lack elastic fibers, have absent or incomplete smooth muscle, and vary in appearance from stellate or staghorn to barely conspicuous because of stromal compression. Stromal cells have plump nuclei and tend to radiate around the vessels. An abundance of mast cells in the stroma and a lack of other inflammatory cells exist. Localized areas of myxomatous degeneration may be observed in the stroma.

Medical therapy
Hormonal therapy
The testosterone receptor blocker flutamide was reported to reduce stage I and II tumors to 44%.
Despite tumor reduction with hormones, this approach is not routinely used.

Schuon et al reported on the immunohistochemical analysis of growth mechanisms in juvenile nasopharyngeal angiofibroma. They concluded that juvenile angiofibroma (JNA) growth and vascularization are driven by factors released from stromal fibroblasts. Therefore, inhibition of these factors might be beneficial for the therapy of inoperable JNA.

Radiotherapy
Some centers have reported 80% cure rates with radiation therapy. However, concerns regarding potential effects of radiation make radiation therapy a nonuseful modality in most cases.
Stereotactic radiotherapy (ie, Gamma knife) delivers a lower dose of radiation to surrounding tissues. However, most authorities reserve radiotherapy for intracranial disease or recurrent cases.
Three-dimensional conformal radiotherapy in extensive JNA or intracranial extension provides a good alternative to conventional radiotherapy regarding disease control and radiation morbidity.

Surgical therapy
A lateral rhinotomy, transpalatal, transmaxillary, or sphenoethmoidal route is used for small tumors .
The infratemporal fossa approach is used when the tumor has a large lateral extension.

Preoperative details
Preoperative embolization can be accomplished using reabsorbable microparticulate substances (eg, Gelfoam, polyvinyl alcohol, dextran microspheres) or nonabsorbable microparticulates (eg, Ivalon, Terbal). Limit blood loss during surgery is essential.

complications
Excessive bleeding can occur. With improvement in diagnostic imaging techniques and preoperative embolization, the need for blood transfusion has been greatly reduced. Low-grade consumption coagulopathy may complicate small JNA and implies that preoperative coagulation screening may have a role in perioperative hemostasis.
Malignant transformation has been reported in 6 cases; 5 of these patients were treated with radiotherapy, according to a study by Malek et al.

Transient blindness has been reported as a result of embolization, but it is a rare occurrence.
Osteoradionecrosis and/or blindness due to optic nerve damage may occur with radiotherapy.

Fistula of the palate at the junction of the soft and hard palate may occur with the transpalatal approach but is prevented by preservation of the greater palatine vessels during flap elevation.

Anesthesia of the cheek is a frequent occurrence with the Weber-Ferguson incision.


OUTCOME AND PROGNOSIS

The presence of tumor in the pterygoid fossa and basisphenoid, erosion of the clivus, intracranial extension, feeders from the internal carotid artery, a young age, and a residual tumour were risk factors associated with the recurrence of juvenile nasopharyngeal angiofibroma.

mohweh
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Re: nasoppharyngeal angiofibroma

Post by Dr Sarhan on Wed Mar 19, 2008 10:41 am

Thanks
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Re: nasoppharyngeal angiofibroma

Post by dr_totti on Wed Mar 26, 2008 9:34 am

Thanks Dr
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Re: nasoppharyngeal angiofibroma

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