Giant gossypiboma presenting as a pelvic mass

Gossypiboma is a foreign object, such as a mass of cotton matrix or a sponge, that is left behind in a body cavity during surgery. It is uncommon, mostly asymptomatic, and hard to diagnose. It may be incorrectly diagnosed preoperatively, which can lead to unnecessary invasive diagnostic procedures and operations. It should be included in the differential diagnosis of soft-tissue masses detected in patients with a history of a prior operation. We present a case of 36-year-old female who referred to emergency room with severe abdominal pain and distension. Imaging revealed a giant intra-abdominal mass resembling a soft tissue tumor, but revealed to be a giant gossypiboma caused by a sponge that was forgotten during previous ectopic pregnancy surgery. This case differs from others with the absence of findings supporting gossypiboma such as calcification or trapped gas bubbles and emphasizes the importance of this potentially life-threatening complication of surgery.