Figure 4

Resected desmoid tumor. (a) A gross appearance of the tumor (white arrow) seemed like a sub-mucosal tumor. (b) Hematoxylin and eosin (H&E, ×40) stain demonstrated that the tumor was directly involved in the muscularis propria of the transverse colon (left), and was very close to the duodenal muscularis propria (right). The broken line indicates the border between the muscularis propria (*) and the tumor (**). (c) H&E (×400) stain demonstrated spindle cells proliferation and fibroblast-like cells with bland nuclear morphology (upper left). Immunohistochemical analysis indicated tumor cells were negative for c-Kit (upper right), α-smooth muscle actin (lower left), but positive for β-catenin with nuclear accumulation (lower right). (d) Tumor sequence indicated a substitution of GCC (threonine) for ACC (alanine) at codon 41.