Gynecomastia is a condition that causes an increase in breast tissue in males, resulting in larger breasts. It can affect one or both breasts, and can sometimes cause discomfort or nipple tenderness.
Gynecomastia typically looks and feels like a button-sized growth underneath your nipple. You may be able to see this as a breast lump or feel it when you press on the area. The lump may move easily within the breast tissue and may be tender to touch. Breast lumps and enlargement may occur in one or both breasts.