Neoplasms, or tumors, are growths of new cells that multiply faster than normal cells, states Johns Hopkins Medicine. These growths may be benign or malignant. Without treatment, even non-cancerous, or benign, tumors may grow unchecked and damage surrounding tissue and structures.
Although benign tumors may cause problems due to their growing size, they do not spread to other parts of the body, advises Johns Hopkins Medicine. They usually do not return after removal. Malignant, or cancerous, tumors not only grow locally, but also spread to other parts of the body. The spread of malignant neoplasms is called metastasis, states Worldwide Cancer Research. Even after removal, cancerous neoplasms may return.
Malignant neoplasms have different names depending on their origin. For example, malignant neoplasms in the skin are called carcinomas, and malignant neoplasms originating in the connective tissue are called sarcomas, states the University of Utah. Regardless of where a malignant neoplasm originates, it may spread to the surrounding tissue or other parts of the body through the lymph system or blood steam.
Cancerous tumors are cells in the body that, due to a damaged gene, multiply abnormally, according to Worldwide Cancer Research. Although genes play a role in cancer, it is not an inherited disease.