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Juvenile nasopharyngeal angiofibroma

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JUVENILE NASOPHARYNGEAL ANGIOFIBROMA

JUVENILE NASOPHARYNGEAL ANGIOFIBROMA- Dr. Praneeth

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IntroductionUncommon, benign and extremely vascular tumourUp to 0.5% of head and neck tumoursOccurring almost exclusively in malesAverage age of onset - 15 years old

JNA Facts and StatisticsIntracranial Extension between 10-20%Recurrence Rates as high as 50%

Origin - Posterolateral nasal wall at the sphenopalatine foramen

AnatomySphenopalatine foramen Contents sphenopalatine artery, nerves nasopalatine, posterior superior nasal.

Anatomy contLocally invasive.Spread submucosallyExtension - Medially into nasopharynx or nasal cavity Laterally into Infratemporal fossa middle cranial fossa Pterygopalatine fossa infraorbital fissure orbit

Anatomy contVascular supply Most commonly from internal maxillary arteryAlso : internal carotid, external carotid, common carotid, ascending pharyngeal

Anatomy cont

Fossa of rosenmuller

Situated at the corner between lateral and dorsal walls of nasopharynx. Not obvious in infantsMeasures upto 1.5 cm in depth in adultsOpens into nasopharynx at a point below foramen lacerum.

Anatomy contBoundaries Ant Eustachian tube & Levator veli palatiniPost Pharyngeal wall mucosa overlying pharyngobasilar fascia & retropharyngeal space containing nodes of rouviereMed nasopharyngeal cavityPosterolateral (apex) carotid canal opening and petrous apex posteriorly, foramen ovale & spinosum laterally Lat Tensor veli palatini, mandibular nerve, prestyloid compartment of parapharyngeal space.

Anatomy contRoof of the fossa of rosenmuller Formed by foramen lacerumStructures passing near it Internal carotid arteryGreater superficial petrosal nerveAscending palatine artery Through this foramen, tumours from fossa of rosenmuller invades intracranial structures. III, IV, V, VI cranial nerves are located near to this foramen, which are commonly involved when tumours invade intracranial structures via the foramen lacerum.

PATHOGENESIS

PathologyMacroscopic Well-defined, spongy lobulated tumours with nodules covered by nasopharyngeal mucosa (squamous epithelium).Nodularity increases with age.Color varies from pink (part seen in nasopharynx) to white or grey (extrapharyngeal areas).On section, tumour is reticulated, whorled or spongy in appearance lacking a true capsule. Edges are sharply demarcated and easily distinguishable from the surrounding tissues.

Pathology contMicroscopic Consists of proliferating, irregular vascular channels within a fibrous stroma. Vascular component is more in young tumours and as age increases, collagen content increases.Fibrous tissue increases towards periphery and vascular element tends to be more central.

Pathology cont Tumour blood vessels typically lack smooth muscle and elastic fibres, this is the reason for sustained bleeding.Cellular infiltration with plasma cells, lymphocytes, polymorphs, eosinophils can be present.Stromal compartment consists spindle or stellate plump cells that give rise to varying amounts of collagen which makes some tumours very hard or firm.Mucous glands can be seen in superficial parts of the tumour underneath the epithelial covering.

Pathogenesis This tumour is almost exclusively found in adolescent boys, so there is much speculation and indirect evidence that sex-hormone receptors play some part in its development. Theories associated with its aetiopathogenesis - Ringertz theory (1938) JNA always arose from the periosteum of the skull base.Som & Neffson (1940) inequalities in the growth of bones forming skull base resulted in hypertrophy of the underlying periosteum in response to hormonal influence.Bensch & Ewing (1941) tumour probably arose from embryonic fibro cartilage between basi-occiput and basi-sphenoid. Brunner (1942) suggested origin from conjoined pharyngobasilar and buccopharyngeal fascia.

Pathogenesis contMarten et al (1948) proposed a hormonal theory suggesting that these tumours resulted from deficiency of androgens or overactivity of estrogens and that the hormonal stimulation is responsible for angiomatous components seen in JNA.Sternberg (1954) proposed that JNA could be a type of hemangioma like a cutaneous hemangioma seen in children which regresses with age.Osborn (1959) it could be due to either a hamartoma or residual fetal erectile tissue which were subjected to hormonal influence.Girgis & fahmy (1973) observed cell nests of undifferentiated epitheloid cells or zellballen at the growing edge of angiofibromas and so considered it as a paraganglioma.

Pathogenesis contThe most accepted theory is that JNAs originate from sex steroid stimulated hamartomatous tissue located in the turbinate cartilage. The proposed hormonal influence explains why some JNAs involute after puberty.

Recent immunocytochemical techniques shown that androgen receptors are present in at least 75 percent of tumours, these receptors are present in both the vascular and stromal elements. progesterone receptors were found in some. In contrast, oestrogen receptors have not been demonstrated ?

Pathogenesis contOther factors that play a role in the growth of this tumour are The angiogenic growth factor (vascular endothelial growth factor (VEGF)) has been found localized on both endothelial and stromal cells, indicating both cell types play a role in tumour development. Vessel density and both the expression and localization of VEGF correlate with the proliferative marker Ki67.But both of them do not have any relation to its degree of aggressiveness.Overexpression of insulin-like growth factor II (IGFII) found in a large number of juvenile angiofibromas. IGFII gene is situated on the chromosome 11q.associated with a tendency to recurrence and poorer prognosis.

Pathogenesis contSporadic juvenile angiofibromas develop 25 times more frequently in patients with familial adenomatous polyposis (FAP), a condition that is associated with the germline mutations of adenomatous polyposis coli (APC) gene present on chromosome 5q.This gene regulates the beta-catenin pathway which influences cell to cell adhesion. Mutations of beta-catenin have been found in recurrent juvenile angiofibromas also.Beta-catenin localised only in the nuclei of stromal cells suggest that these cells have a critical role in the development of these neoplasms.

PathophysiologyThe proposed origin of JNA is located along postero-lateral wall in the roof of nasopharynx, usually in the region of the superior margin of the sphenopalatine foramen and the posterior aspect of the middle turbinate.Fetal histology confirms large areas of endothelial tissues in this region.Rather than invading surrounding tissue, this tumour displaces and distorts, relying on pressure necrosis to destroy and push through its bony confines. Intracranial extension is noted in 10-20% of cases.JNA are seldom seen in children below the age of 8.Rate of growth of tumour and period of maximum development coincides with rate of erectile tissue of penis, both increasing in size during the period of sexual development.

PRESENTATION

Clinical featuresNasal obstruction Intermittent unprovoked epistaxesChronic anaemia may be present due to repeated epistaxis.Complete nasal obstruction may cause stasis of secretions and may also lead to sepsis.Patients may have hyposmia or anosmia.

2 cardinal symptoms

Clinical features contVoice acquires a nasal intonation and may become plummy if swelling enlarges to force the soft palate down.Blockage of ET orifice may cause deafness and otalgia.Headache may be present due to chronic sinusitis history or intracranial extension.Pressure on optic chaisma due to erosion of mass into the cranial cavity may cause diplopia.Tenting of the optic nerve by tumour mass may cause failing vision ( as observed by shaheen et al).

Clinical features cont

On Anterior rhinoscopy Abundant purulent nasal secretions.Bowing of nasal septum to uninvolved side.

On Posterior rhinoscopy Pink or red mass filling the nasopharynx can be seen.

Clinical features contWhen disease becomes extensive involving nose and infratemporal fossa, gross physical signs will be seen Nasal bones become spayed out, Swelling in the temple and cheek occur.Intraoral palpation in the interval between ascending ramus of the mandible and the side of the maxilla may reveal the thickening of disease which has crept around the back of the antrum.Impaction of bulky mass in the infratemporal fossa results in trismus and bulging of the parotid.Proptosis is seen if orbital fissures are penetrated.Frog face appearance may be seen if tumour is extensively spread involving the ethmoidal region.

Extension of the tumourIt follows the lines of least resistance It mostly arises from SPF area. It may have 2 components one filling the nasopharynx and the other extending out into the pterygopalatine and infratemporal fossa.Central stalk joining the 2 components occupy the SPF at the upper end of the vertical plate of palatine bone.1> hangs down in the nasopharynx and may depress the soft palate when large enough2> may grow into I/L nasal passage towards anterior nares. It can cause pressure on lateral wall and also on septum bending it to opposite side. Corresponding turbinates and ethmoidal air cells and the related antral wall may suffer pressure atrophy. Lateral spread into the maxillary sinus may be responsible for the cheek swelling.3> it can encroach into the orbit through infra orb