What could cause chest enlargement and wider areola in a 15-year-old boy?

The symptoms you’re describing—enlargement in the chest area and widening of the areola—are characteristic of a condition called gynecomastia. This condition is relatively common in adolescent boys and is typically due to hormonal changes during puberty. Gynecomastia occurs when there’s an imbalance between the hormones estrogen and testosterone, which can cause breast tissue to grow. It’s important to note that it’s not uncommon and often resolves on its own as hormone levels stabilize over time. You mention no major pain, which is usual, though some tenderness can occasionally be present in gynecomastia cases. Since you noted that this started a few years ago, it might be helpful to evaluate whether there are any other symptoms that might suggest a more significant hormonal imbalance or medical condition, such as significant weight gain or loss, changes in pubic or facial hair, or any other signs of systemic issues. Though gynecomastia can persist, it’s often self-limiting and benign. However, if it causes significant concern or distress, or if there are other accompanying symptoms, it is reasonable to seek a clinical evaluation. A healthcare professional can assess hormone levels through blood tests and perform a physical examination. In rare cases, imaging like a breast ultrasound might be indicated. While waiting for the condition to possibly improve on its own, maintaining a healthy lifestyle with regular exercise and a balanced diet is advantageous. If the enlargement persists into adulthood or affects quality of life significantly, surgical options can be considered. Consulting an endocrinologist might be a prudent next step if there’s concern about ongoing hormonal imbalance. If you notice any rapid changes, significant asymmetry, or systemic symptoms, seek medical attention promptly.