A 57-year-old man in Japan had been coughing hard for a week from pneumonia when a new pain appeared on the right side of his belly. A bruise spread across his abdomen, and scans showed pools of blood inside one of his abdominal muscles. While doctors monitored him, his heart began racing, and his circulation became unstable.
The diagnosis was a rectus sheath hematoma, bleeding within the long "six-pack" muscle that runs down the front of the abdomen. What made the case, published in February 2026 in JMA Journal, stand out is what the man did not have. He was not taking blood thinners or antiplatelet drugs, his clotting was normal, and he had never had surgery.
