Description
Juvenile nasopharyngeal angiofibroma (JNA) is a benign but locally aggressive vascular tumour that originates in the nasopharynx. It is characterised by proliferation of fibrous tissue and blood vessels. It represents the most common of the benign nasopharyngeal neoplasms. It occurs almost exclusively males and presents with nasal obstruction and epistaxis.
Pathogenesis
The exact cause of JNA is unknown, but it is believed to be hormone-dependent due to its occurrence in adolescent males and its regression after puberty. There may also be a genetic component as some cases are associated with familial adenomatous polyposis.
Epidemiology, Risk Factors & Associations
- JNA is rare, accounting for less than 0.05% of all head and neck tumours.
- It predominantly affects adolescent males (9:1 male to female ratio) with a peak incidence between 14 and 25 years of age.
Clinical Features
The classic clinical presentation includes unilateral nasal obstruction, recurrent epistaxis, and, in advanced cases, facial swelling or deformity. Other symptoms may include headache, hearing loss, and symptoms related to local invasion such as diplopia.
Complications
- May present with life-threatening epistaxis.
- Local invasion can lead to serious complications including cranial nerve palsies, proptosis, and intracranial extension potentially causing increased intracranial pressure.
Pathological Features
Histopathology
- Composed of stellate and spindle-shaped cells with vascular and fibrous stromal components.
Radiological Features
General Imaging Features
- Well-defined, enhancing lobulated soft tissue mass centred in the sphenopalatine foramen or pterygopalatine fossa, often extending into the posterior nasal cavity, and sinuses
- Widening of the sphenopalatine foramen and pterygomaxillary fissure
- There is usually erosion of bone behind the sphenopalatine fossa, with extension to the upper medial pterygoid plate.
- Extension into the middle cranial fossa is possible if there is erosion of the pterygoid base
CT
- Hyperdense soft tissue mass causing bony remodeling and destruction
- Holman-Miller sign refers to forward bowing of the posterior wall of the maxillary sinus
- Post–Contrast: Marked enhancement reflecting prominent vascularity
MRI
- T1: Isointense to muscle. Salt and pepper appearance representing flow voids may be seen.
- T2: Heterogenous with dark flow voids.
- Gd+: Intense homogenous enhancement
DSA
- Typical supply is via the external carotid artery; internal maxillary artery, ascending pharyngeal artery and palatine artery.
- Supply via the internal carotid artery is less common.
- Demonstrates vascular blush
- Enlargement of the feeding vessel is not usually seen.
Nuclear Medicine
- Not typically used for evaluation of JNA
Grading and Staging
Radkowski Staging System
- Stage IA – Tumour limited to the nasal cavity and/or nasopharynx.
- Stage IB – Tumour involving the nasal cavity and/or nasopharynx with extension into one or more sinuses (ethmoid, sphenoid, maxillary).
- Stage IIA – Tumour extends into the pterygopalatine fossa.
- Stage IIB – Tumour involves the pterygopalatine fossa with extension into the infratemporal fossa or the orbital apex without bone destruction.
- Stage IIC – Tumour with erosion or destruction of the bones of the skull base, involving the middle cranial fossa, cavernous sinus, or optic chiasm.
- Stage IIIA – Tumour with extensive intracranial extension with no or minimal dural involvement.
- Stage IIIB – Tumour with extensive intracranial extension with significant dural involvement.
University of Pittsburgh Medical Center (UPMC) Staging System
- Stage I – Tumour limited to the nasopharynx, nasal cavity, or sphenoid sinus.
- Stage II – Tumour involving the pterygopalatine fossa or the maxillary, ethmoid, or sphenoid sinuses with bone destruction.
- Stage III – Tumour with infratemporal fossa extension or intracranial extension without cavernous sinus, pituitary fossa, or optic chiasm involvement.
- Stage IV – Tumour with intracranial extension involving the cavernous sinus, pituitary fossa, or optic chiasm.
Differential Diagnosis
- Nasal polyp: More common in adults, does not cause bone destruction
- Nasopharyngeal carcinoma: More common in adults. Not typically hypervascular. Lymph node involvement is usually seen (up to 90% of cases).
- Rhabdomyosarcoma: More aggressive with greater bony destruction, often causes rapidly progressive symptoms. Usually less hypervascular than JNA. Usually arises from orbit, sinonasal area and temporal bone.
- Langerhan Cell Histiocytosis: Frequently presents as an enhancing mass with bony destruction and intracranial extension however usually involves the orbit, mandible, mastoid temporal bone, or calvarium. Not a hypervascular lesion.
Management
Treatment is usually surgical resection (open or endoscopic), with preoperative embolisation often performed to reduce blood loss. Radiation therapy may be used for residual or recurrent disease. Recurrence is often seen when there is skull base involvement.