Nasopharyngeal Angiofibroma (Nasopharyngeal Fibroma /Juvenile Nasopharyngeal Angiofibroma) : Definition, Etiology, Pathophysiology, Symptoms, Diagnosis, & Management
- Nasopharyngeal Angiofibroma benign tumours of nasopharynx. Angiofibroma is made up of vascular and fibrous tissues.
- It is the commonest of all benign tumours of nasopharynx. However, it is a rare tumour.
- The exacr cause of Nasopharyngeal Angiofibroma is unknown. As the tumour is predominantly seen in adolescent males in the second decade of life, it is thought to be testosterone dependent. Such patients have a hamartomatous nidus of vascular tissue in the nasopha rynx and this is activated to form angiofibroma when male sex hormone appears.
- Angiofibroma is made up of variable ratio of vascular and fibrous tissues. Mostly, the vessels are just endothelium-lined spaces with no muscle coat. This accounts for the severe bleeding as the vessels lose the ability to contract, and also the bleeding cannot be controlled by application of adrenaline.
Extensions of Nasopharyngeal Fibroma
Nasopharyngeal Angiofibroma is a benign tumour but locally invasive and destroys the adjoining structures. It may extend into :
- Nasal cavity causing nasal obstruction, epistaxis and nasal discharge .
- Paranasal sinuses : Maxillary, sphenoid and ethmoid sinuses can all be invaded.
- Pterygomaxillary fossa, infratemporal fossa and cheek.
- Orbits giving rise to proptosis and “frog-face deformity”. It enters through the inferior orbital fissure and a lso destroys apex of the o rbit. It can also enter the orbit through superior orbital fissure.
- Cranial cavity. Middle cranial fossa is the most common. There are two routes of entry either by erosion of floor of middle cranial fossa, anterior to foramen lacerum. The tumour lies lateral to carotid artery and cavernous sinus.
- Through sphenoid sinus, into the sella. Tumour lies medial to carotid artery.
- Anterior cranial fossa (through ethmoid roof or cribriform plate).
- Age and sex : Tumour is seen almost exclusively in males in the age group of 10-20 years. Rarely, it may be seen in older people and females.
- Profuse and recurrent epistaxis : This is the most common presentation . Patient may be markedly anaemic due to repeated blood loss.
- Proggressive nasal Obstruction and denasal speech due to mass in the postnasal space.
- Conductive hearing loss and serous otitis media due to obstruction of eustachian tube.
- Mass in the nasopharynx : Tumour is sessile , lobulated or smooth and obstructs one or both choanae . It is pink or purplish in colour. Consistency is firm but digital palpation should never be done until at the time of operation.
- Other clinical features like broadening of nasal bridge, proptosis, swelling of cheek, infratemporal fossa or involvement of lInd, llIrd, IVth, Vlth cranial nerves will depend on the extent of tumour.
- Soft tissue lateral film of nasopharynx shows soft tissue mass in the nasopharynx.
- X-rays of paranasal sinuses and base of skuII may show displacement of nasal septum, opacification of sinuses, anterior bowing of posterior wall of maxillary sinus, destruction of medial antral wall, erosion of greater wing of sphenoid or pterygoid plates, widening of lower lateral margin of superior orbital fissure.
- CT scan of the head with contrast enhancement is now the investigation of choice. It has replaced conventional radiographs. It shows the extent of tumour, bony destruction or displacements. Anterior bowing of the posterior wall of maxillary sinus (often called the antral sign) ipathognomic of angiofibroma.
- Magnetic resonance imaging (MR1) is complementary to CT scans, when soft tissue extensions are
present intra-cranially, in the infratempral fossa or into the orbit.
- Carotid angiography shows extenion of tumour, its vascularity and feeding vessels. It is done when embolisation is planned before operation.
- It is mostly based on clinical picture.
- Biopsy of the tumour is attended with profuse bleeding and is therefore, avoided. If it is essential to differentiate it from other tumours, biopsy can be done under general anaesthesia with all arrangements to control bleeding and transfuse blood.
1. Surgery : Earlier, nasopharyngeal angiofibromas were considered to undergo spuntaneous regression with advancement of age but in practice it doesn’t happen. Various surgical approaches to angiofibroma, depending on origin & extensions, are iisted below.
- Transpalatine + Sublabial (Sardana’s approach)
- Extended lateral rhinotomy via facial incision or degloving approach
- Extended Denker’s approach
- Intra cranial – Extracranial
- Infratemporal fossa
2. Radiotherapy : A dose of 3000 to 3500 cGy in 15-18 fractions is delivered in 3-3.5 weeks. Response is not immediate. Tumour regresses slowly in about a year, sometimes even up to 3 years. Radiotherapy is also used for intracranial extension of disease when tumour derives its blood supply from the internal carotid system. Recurrent angiofibromas have also been treated by intensity modulated radiotherapy-a newer mode of treatment.
3. Hormonal : Since the tumour occurs in young males at puberty, hormonal therapy as the primary or adjunctive treatment has been used. Diethylstilboestrol and flutamide have been used .
4. Chemotherapy : Recurrent and residual lesions have been treated by chemotherapy, doxorubicin, vincristine and dacarbazine in combination.