Question: how big is a 2 cm tumor?
Answer: Tumor size. Primary breast tumors vary in shape and size. The smallest lesion that can be felt by hand is typically 1.5 to 2 centimeters (about 1/2 to 3/4 inch) in diameter. Sometimes tumors that are 5 centimeters (about 2 inches) — or even larger — can be found in the breast.