Fig. 4

Macroscopic findings indicated a 35 × 30 mm submucosal tumor-like lesion in the sigmoid colon. The black and red solid lines indicate the deposition of amyloid protein (a). There was no amyloid protein in the margins. A sliced section showed a poorly circumscribed, yellowish lesion with hemorrhage within the colon wall (b). Histopathological findings indicated that the epithelial integrity of the mucosa was preserved, and eosinophilic material was present in the submucosal and deeper layers (hematoxylin and eosin staining × 40) (c). Eosinophilic material was structureless (H&E × 100) (d). This tumor was positive for Congo-red staining (× 100) (e)