A resection device and method permits safe and efficient encapsulation, isolation and resection of body tissue. The device includes a sheath of flexible and severable material configured to receive the body tissue to be resectioned as it is drawn therein. The sheath may be expandable and held in an expanded condition as the body tissue to be resectioned is drawn into the sheath. Thereafter, the sheath is permitted to collapse about the body tissue to contain and constrict the body tissue. Once the body tissue to be resectioned is disposed in the sheath, the sheath is severed to resection the body tissue.