Unilateral proptosis as the primary presentation of Stage IVb Juvenile Nasopharyngeal Angiofibroma with direct external carotid artery supply: Case report.

Juvenile Nasopharyngeal Angiofibroma (JNA) is a benign, hypervascular tumor that typically presents with nasal symptoms. However, when it presents with isolated ophthalmic features, it can lead to significant diagnostic pitfalls. We report a rare "ophthalmic-first" presentation of a Stage IVb JNA in a 19-year-old male. The patient presented only with progressive unilateral proptosis for 7 months, initially misdiagnosed as a traumatic carotid-cavernous fistula due to a history of minor head trauma. Advanced imaging (computed tomography and magnetic resonance imaging) corrected the diagnosis by identifying a 72 × 49 mm nasopharyngeal mass with a positive Holman-Miller sign and characteristic "flow voids". Unique to this case, computed tomography Angiography revealed a direct arterial feeder originating from the external carotid artery rather than the typical maxillary artery. Based on Fisch Stage IVb classification, the tumor demonstrated extensive local aggression, invading the orbit and compressing the left temporal lobe. This case highlights a diagnostic challenge where JNA presented with an atypical "ophthalmic-first" manifestation, mimicking a carotid-cavernous fistula, because the patient only complained of proptosis and overlooked his nasal symptoms. Radiologically, the tumor was advanced (Fisch Stage IVb) and exhibited a unique vascular pattern with a direct feeding branch from the external carotid artery, significantly increasing the risk of massive hemorrhage. Due to these multidisciplinary management challenges, the patient required specialized preoperative embolization and vascular control. However, the case highlights a common clinical hurdle, as the patient was lost to follow-up before intervention. This highlights the need for high clinical suspicion and a centralized tracking system for managing such complex, high-risk vascular tumors. JNA must be considered in the differential diagnosis of adolescent males presenting with unilateral proptosis, even when classic symptoms like epistaxis are mild or initially underreported by the patient. Identifying atypical vascular patterns, such as direct feeders from the external carotid artery, is essential for meticulous surgical planning and effective hemorrhage control in advanced Stage IVb cases.