Juvenile nasopharyngeal angiofibroma (JNA) is a benign but highly vascular and locally aggressive tumor, primarily affecting adolescent males. Imaging is central for diagnosis, characterizing extent, and guiding management, especially preoperative planning and intervention.
Imaging Features
- Location and Appearance: The mass typically arises from the posterior nasal cavity near the sphenopalatine foramen and nasopharynx, often extending into the pterygopalatine fossa, paranasal sinuses, infratemporal fossa, or even intracranially.
- CT Findings: Shows a well-defined, lobulated soft-tissue mass causing expansion and remodeling of adjacent bony structures, such as anterior bowing of the posterior wall of the maxillary antrum and erosion of contiguous bones. There may be deviation of the nasal septum or mass effect on neighboring spaces.
- MRI Findings: Demonstrates a highly vascular mass with avid contrast enhancement. T2-weighted images reveal intermediate-to-high signal intensity with multiple flow voids reflecting rapid blood flow. Extension into the paranasal sinuses, orbit, skull base, and cranial cavity is more accurately depicted. The tumor often causes expansion rather than frank destruction of structures.
- Angiography: Reveals a pronounced tumor blush, feeding primarily from internal maxillary, ascending pharyngeal, and sometimes contralateral external carotid branches. This is essential in mapping for preoperative embolization.
- Other Features: Biopsy is avoided due to the risk of catastrophic bleeding; diagnosis is established by clinical and radiological findings.[Primer-of-Diagnostic-Imaging-6E][Chapman-Nakielnys-Aids-to-Radiological-Differential-Diagnosis-7E]
Role of Radiological Intervention
- Preoperative Embolization: Endovascular embolization of the tumor's feeding vessels is a key intervention performed 24–72 hours before surgery to reduce intraoperative blood loss and operative morbidity.
- Mapping Vascular Supply: Digital subtraction angiography is used preoperatively to identify the specific arterial supply and plan selective embolization.
- Follow-Up Imaging: Post-embolization imaging evaluates devascularization and assesses for residual or recurrent tumor after surgery. MRI is particularly valuable for follow-up, given its multiplanar capability and lack of radiation.
- Definitive Therapy (Rarely): In select, surgically inoperable cases or residual tumors, staged embolization may be considered for palliative control, although primary treatment remains surgical excision facilitated by preoperative embolization.[Primer-of-Diagnostic-Imaging-6E][Chapman-Nakielnys-Aids-to-Radiological-Differential-Diagnosis-7E]