Surgical strategies for localized colorectal amyloidosis

BACKGROUND: Localized colorectal amyloidosis has a good prognosis, but cases involving bleeding or perforation may require surgery. However, there are few case reports discussing the differences in the surgical strategy between the segmental and pan-colon types. CASE PRESENTATION: A 69-year-old woman with a history of abdominal pain and melena was diagnosed with amyloidosis localized in the sigmoid colon by colonoscopy. Since preoperative imaging and intraoperative findings could not rule out malignancy, we performed laparoscopic sigmoid colectomy with lymph-node dissection. Histopathological examination and immunohistochemical staining revealed a diagnosis of AL amyloidosis (λ type). We diagnosed localized segmental gastrointestinal amyloidosis, because there was no amyloid protein in the margins, and the tumor was localized. There were no malignant findings. CONCLUSIONS: Unlike systemic amyloidosis, localized amyloidosis has a favorable prognosis. Localized colorectal amyloidosis can be classified into the segmental type, in which amyloid protein is deposited locally, and the pan-colon type, in which amyloid protein is deposited extensively in the colon. Amyloid protein causes ischemia due to vascular deposition, weakening of the intestinal wall due to muscle layer deposition, and decreased peristalsis due to nerve plexus deposition. No amyloid protein should remain outside the resection area. The pan-colon type is often reported to cause complications such as anastomotic leakage, and primary anastomosis should be avoided. On the other hand, if there is no contamination or tumor remnants in the margin, the segmental type may be considered for primary anastomosis.