Rectus sheath abscess caused by perforation of the small bowel by a fish bone

Gastrointestinal perforation resulting from ingestion of foreign bodies is uncommon, with a frequency of less than 1%. There is only one report in the literature of an abscess from a foreign body extending to the rectus sheath muscle in a patient who presented with chronic abdominal pain for several years. We report a 55-year-old man who presented to the emergency department with complaints of acute abdominal pain and an abdominal wall mass after severe coughing. A rectus sheath hematoma was impressed after a computed tomography study, but his symptoms were refractory to medical treatment. Ultrasonography revealed a foreign body within the mass. A fish bone with abscess formation was found during the surgery. Emergency physicians should maintain a high index of suspicion for an occult retained foreign body in any abscess and consider etiologies other than rectus sheath hematoma if the patient has signs of infection, leukocytosis, or progression of peritonitis. Abdominal ultrasonography may diagnose foreign bodies that are missed by computed tomography.