Benign neoplasm is a medical term used to describe a non-cancerous type of tumour. It is a descriptive term that includes many different types of non-cancerous tumours. Benign neoplasms can start anywhere in the body and the specific type of tumour depends on the kind of cells found inside the tumour. The opposite of a benign neoplasm is a malignant neoplasm. Unlike a malignant neoplasm, the cells in a benign neoplasm will not spread to other parts of the body. However, a benign neoplasm can continue to grow in size over time and large tumours can damage surrounding organs and tissues.
Benign neoplasm is considered a preliminary diagnosis because it does not say anything about the types of cells in the tumour. Pathologists often use this term when they do not have enough information about the tumour to make a more specific or final diagnosis. This may happen after only a small sample of the tumour is removed in a procedure called a biopsy. Additional tests such as immunohistochemistry, fluorescence in situ hybridization (FISH), in situ hybridization, and next-generation sequencing (NGS) may be performed to help better characterize the tumour. A more specific or final diagnosis can often be reached after the entire tumour is removed and examined under the microscope.