Ki-ras gene mutations are invariably present in low-grade mucinous tumors of the vermiform appendix.

Objective: Low-grade mucinous tumors of the appendix appear to have a simple histological structure. Paradoxically, reports have suggested a greater frequency of Ki-ras gene mutation in these lesions than in more complex lesions such as benign colonic adenomas and carcinomas. We assessed several molecular genetic changes, including Ki-ras gene mutations, in a large series of low-grade mucinous tumors of the appendix.

Rapid progression of littoral cell angioma of the spleen in a man with multiple infections.

Littoral cell angioma is an uncommon primary vascular neoplasm of the spleen. It frequently follows a benign course, but cases with aggressive behavior have been described. We present a case of this rare disease highlighting radiological examinations showing a rapid increase in the size of the spleen as well as an increase in the number and size of existing nodules.

Molecular genetic changes associated with colorectal carcinogenesis are not prognostic for tumor regression following preoperative chemoradiation of rectal carcinoma.

Purpose: Preoperative chemotherapy and radiation has become the standard of care for many patients with rectal cancer. The therapy may have toxicity and delays definitive surgery. It would therefore be desirable to identify those cancers that will not regress with preoperative therapy.