What type of tumors are adenomas?

Adenomas are classified as benign tumors that develop from glandular epithelial tissue. This means they originate from the cells that line glands in the body, such as the thyroid, pituitary, and adrenal glands, as well as other organs. These tumors typically remain localized and do not invade surrounding tissues or metastasize, which is a key distinction between benign and malignant tumors.

The diagnosis of adenomas relies on their characteristic histological features, where these tumors maintain some degree of differentiation and can exhibit a well-defined capsule. They often present with minimal symptoms unless they grow large enough to cause pressure on adjacent structures or produce hormones.

When considering the other options available, malignant tumors of epithelial origin refer to carcinomas, which are distinctly different as they exhibit uncontrolled growth and invasive properties. Metaplastic tumors involve a transformation of one type of tissue into another, while neurogenic tumors are derived from nerve tissue. Thus, the defining quality of adenomas being benign tumors of glandular epithelial origin is what makes this option the correct one.