There are several similarities as well as differences between malignant and benign tumors.
Synonyms of malignant in medicine include cancer, virulent, or malevolent.
That said, some malignant conditions are very treatable, whereas some benign conditions may be life-threatening.

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Malignant Conditions
Not all malignant conditions are cancerous.
Isn’t that obvious?
Yet it can sometimes be difficult to tell the difference even under the microscope.
In addition, in many tumors, there is a mixture of normal, precancerous, and cancer cells.
Advances in the treatment of some cancers have greatly improved survival rates, and some malignancies are highly survivable.
National Cancer Institute.What is cancer?
Institute for Quality and Efficiency in Health Care.How do cancer cells grow and spread?
National Institute of Neurological Disorders and Stroke.Tuberous sclerosis.
2015;7(3):11541177.
Published 2015 Jul 1. doi:10.3390/cancers7030830
National Library of Medicine.