An adenoma is a non-cancerous growth that arises from the cells of a gland or gland-like structure. In sonography, adenomas are most commonly encountered in the thyroid gland, liver, adrenal glands, and parathyroid glands. On ultrasound, a thyroid adenoma typically appears as a well-defined, solid nodule that may have a surrounding halo, while a hepatic adenoma usually looks like a well-circumscribed mass in the liver with variable echogenicity. Although adenomas are benign, they are important to identify because some types can grow large enough to cause symptoms, bleed, or in rare cases undergo malignant transformation.
Sonography Term