2017 Volume 37 Issue 4 Pages 667-671
The patient was a 33-year-old man. He consulted the Emergency and Critical Care Center of our hospital complaining of an upper abdominal pain. A preoperative contrast-enhanced abdominal CT examination revealed torsion of a mucocele of the appendix, and an emergency laparoscopically assisted appendectomy was performed. The resected specimen suggested a swelling of the appendix (9.5×2.5cm), and a yellow-white, jelly-like substance was observed in the inner area. Pathologically, a diagnosis of a low-grade appendiceal mucinous neoplasm (LAMN) was made. The mucus had infiltrated the submucosal layer. LAMN is a newly classification of tumor in the Japanese Classification of Colorectal Carcinoma. A standard treatment for LAMN has not yet been established, but LAMN has both benign and malignant properties, and strict follow-up may be necessary after resection involving a sufficient margin. To our knowledge, only 15 case reports of LAMN torsion have been made in Japan. In addition, a diagnosis of torsion was made before surgery in 2 patients, including our patient. Such cases may be extremely rare.
