Spontaneous rupture with pseudoaneurysm formation in a nodular goiter presenting as a large neck mass.

Acute airway obstruction caused by goiter hemorrhage is a rare but potentially life-threatening condition. We report a case of nodular goiter in which spontaneous rupture with active bleeding developed suddenly, presenting as a large neck mass with dyspnea. Sonographic examination revealed a large inhomogeneous soft tissue mass in the left thyroid lobe containing some hypoechoic areas.