A rare, spontaneous external jugular vein pseudoaneurysm: case report and literature review.

External jugular vein pseudoaneurysm represents an extremely rare venous lesion. We present the case of a 28-year-old female patient with a 2-year history of a left lateral neck mass that suddenly enlarged recently and was accompanied by severe pain. Digital subtraction angiography was applied to further confirm the venous origin of the lesion. The patient underwent complete surgical excision of the mass combined with ligation of the involved venous segment. This case indicates that external jugular vein pseudoaneurysm should be included in the differential diagnosis of lateral neck masses, particularly when the lesion presents with rapid enlargement and acute pain suggestive of secondary thrombosis. Multimodal imaging plays a crucial role in the accurate diagnosis of this rare disease, and complete surgical excision is a safe and effective therapeutic strategy for symptomatic lesions.