Florid Vascular Proliferation of the Small Bowel and Colon, a Potential Masquerader of Malignancy: Report of Three Cases.

Vascular abnormalities and lesions of the small bowel and colon are rare. A florid vascular proliferation (FVP) associated with colon obstruction and intussusception has been described and can mimic malignant vascular tumors such as angiosarcoma. In this article, we report a case of colonic FVP associated with colon obstruction, a case of small bowel FVP associated with a Meckel's diverticulum, and a case of small bowel FVP with intussusception. All cases occurred in older adults (mean 73 years of age, range 62-80 years of age). FVP grossly appeared as a mass-like lesion in one small bowel case, while the other cases did not demonstrate a grossly identifiable mass. Histologically, all cases demonstrated a transmural vascular proliferation with plump endothelial cells. No significant cytologic atypia was seen, and mitotic figures were rare. No recurrence was seen in all cases with an average follow-up of 22 months. It is important to be aware of this entity as it appears to be a nonneoplastic reactive process, unlike some of its histologic mimics.