Spontaneous pseudoaneurysm of the superficial temporal artery in neurofibromatosis type 1: illustrative case.

Background: A pseudoaneurysm of the superficial temporal artery is an uncommon clinical entity that has largely been linked with direct traumatic causes. Neurofibromatosis type 1 (NF1)-related vasculopathy is a rare cause of idiopathic arterial bleeding in the craniofacial region.

Observations: A 46-year-old male with clinical features of NF1 presented to the hospital with an enlarging and tender right temporal mass without a history of trauma. Computed tomography angiography suggested the development of a pseudoaneurysm, and surgery was performed to resect the mass. Histopathological examinations showed focal interruption of the epithelium layer and elastic lamina, well-demarcated thickening of the smooth muscle layers of the arterial wall, supporting the diagnosis of pseudoaneurysm.

Lessons: NF1-associated vasculopathy is likely the predisposing factor for the development of a superficial temporal artery pseudoaneurysm.