Benign tumors can be surgically removed if they're causing symptoms, while the treatment for malignant tumors requires radiotherapy, chemotherapy, and surgery.
The leading cause of that is a pituitary adenoma, which is a benign tumor of the pituitary gland- and this specific condition is called Cushing disease.
A different cause is a hyper functioning thyroid adenoma where the follicular cells start growing uncontrollably, forming a benign tumor that makes excess thyroid hormones.
Another common cause of endogenous Cushing syndrome is tumors of the adrenal glands that make excess cortisol - like adrenal adenomas, which are benign tumors, and adrenal carcinomas, which are malignant tumors.
The exact reason for the development of this sort of benign tumor isn't known - but unlike a malignant tumor - the cells don't invade neighboring tissues or spread to other parts of the body.
Rhabdomyo refers to striated muscle tissue, or cardiac muscle tissue in this case, so rhabdomyomas are benign tumors of the heart that usually affect the ventricles, and are best considered hamartomas rather than a true neoplasm.
There are two general types of tumors: benign tumors and malignant tumors. A benign tumor is composed of cells that will not invade other unrelated tissues or organs of the body, although it may continue to grow in size abnormally.