Rectal tumor outgrowth grade bd1 means 0 to 4 tumor outgrowths, low grade outgrowths. Rectal tumor outgrowth is scattered single cells or clusters of 4 cells in the mesenchyme at the lateral front of the peripheral infiltrate of the tumor. If it is 0-4 tumor outgrowths, it is low-grade outgrowths, classified as bd1; 5-9 tumor outgrowths, intermediate-grade outgrowths, classified as bd2; and ≥10 is high-grade outgrowths, classified as bd3. Rectal tumor outgrowth, which aids in defining the nature of the tumor, is counted using the three-tiered system used by the Japanese Society of Colorectal Cancer. If 0-4 tumors outgrowth, it is a low-grade outgrowth and classified as bd1. If you do not understand the results, you can consult the doctor who performed the test for a detailed explanation of the specific situation.