Postoperative Abdominal Myofascial Pain Syndrome in a Cancer Survivor: A Case Report on Diagnostic and Therapeutic Considerations

Although abdominal myofascial pain syndrome (AMPS) has been reported to cause persistent pain following abdominal surgery, it remains underrecognized, often leading to the development of chronic postoperative pain. We present a case of AMPS characterized by the sudden onset of abdominal pain after esophageal and gastric cancer surgery, which progressed to persistent chronic pain in conjunction with cancer recurrence. Here, we present the case of a 66-year-old man who underwent subtotal esophagectomy and distal gastrectomy for synchronous esophageal and gastric cancers. Approximately one month after surgery, he developed acute abdominal pain. A diagnosis of AMPS was made based on localized abdominal tenderness with a positive Carnett's sign and corresponding hyperechoic findings on ultrasound. A trigger point injection (TPI) with 1% lidocaine provided immediate pain relief. However, the pain later recurred at a different site, which was again effectively managed with TPI. As the cancer recurred and progressed, the area of abdominal pain extended, and the TPI efficacy diminished. Due to intractable pain and functional decline, the patient was transitioned to medical management and ultimately to best supportive care. AMPS can develop acutely in the postoperative course in patients with cancer and may contribute to the development of chronic postoperative pain. Although TPI can be both diagnostically and therapeutically effective, long-term management of AMPS in patients with advanced cancer remains challenging.