She was diagnosed clinically with proctalgia fugax and then underwent extracorporeal magnetic stimulation therapy (EMST). Interestingly, whenever she underwent EMST, she complained of more severe pain. We performed computed tomography to evaluate possible organic causes of the anal pain. This revealed a metallic-density foreign body in the distal rectal posterior wall (Fig. 1A). Endoscopic ultrasonography revealed a 6-mm hyperechoic linear lesion (Fig. 1B). Thus, an acupuncture needle was thought to be the cause of the obscure anal pain.

A group of general surgeons was invited to consult on the case and they concluded that surgery was not clearly indicated because there was no evidence of a complication, such as an abscess. Given the potential complications of surgical removal, we tried medical treatment, and her anal pain improved somewhat with reassurance and gabapentin treatment.

The practice of acupuncture is widely performed in Korea. The acupuncture needle is typically placed in the thicker parts of the body, such as the back or hip, along defined meridians. In most cases, any needle fragments remain in situ forever without problems but sometimes various complications result. The migration of steel needle fragments is possible in response to the magnetic field of a magnetic resonance scanner or EMST.