An aggressive desmoid tumor in a patient with familial adenomatous polyposis: Immunohistochemical findings

A case of an aggressive desmoid tumor in a patient with familial adenomatou s polyposis is described. The lesion rapidly enlarged with compression of a djacent structures including the ureter and small bowel, and the patient di ed because of small bowel perforation and hydronephrosis 3 years after dete ction of small desmoid tumors at the time of a prophylactic coloproctectomy for a colon carcinoma. Immunohistochemically, proliferating cell nuclear a ntigen (PCNA), p21(WAF1/CIP1) and cathepsin D indices, but not the bcl-2 in dex, which were defined as the numbers of immunoreactive tumor cells per 10 00 tumor cells, increased in line with tumor progression. The tumor did not show. staining for collagen IV, but was characterized by intense staining for basic fibroblast growth factor (hFGF). Accordingly, tumor aggression wa s related to increases in both cell proliferation and protease activity, as well as an enhanced expression of bFGF, In addition, the desmoid tumor sho wed deregulation between PCNA and p21(WAF1/CIP1) because the normal inverse relation between these two was not apparent. (Am J Gastroenterol 1999;94:5 30-532. (C) 1999 by Am. Coll. of Gastroenterology).