Differential Diagnosis for a 14-year-old Boy with a Breast Lump
- Single most likely diagnosis
- Gynecomastia: This is the most common cause of breast lumps in adolescent males, characterized by tender, glandular breast tissue. The patient's age, Tanner stage 3 genitalia, and the presence of a tender, glandular mass under the nipple are consistent with this diagnosis. Gynecomastia often occurs during puberty due to hormonal fluctuations.
- Other Likely diagnoses
- Lipoma: A benign tumor composed of fat tissue, which could present as a palpable mass under the nipple. However, lipomas are typically non-tender and not specifically associated with the subareolar region.
- Breast cyst: A fluid-filled sac that can develop in the breast tissue, potentially causing a palpable lump. While less common in males, breast cysts can occur and might be considered if the mass were more fluctuant.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Breast cancer: Although extremely rare in adolescent males, breast cancer must be considered to avoid missing a potentially life-threatening condition. The family history of breast cancer (grandmother at age 64) slightly increases the risk, making it essential not to overlook this possibility.
- Testicular cancer with metastasis: Testicular cancer can metastasize to the breast, presenting as a breast lump. Given the patient's age and normal testicular volume, this is less likely, but it's crucial to examine the testes thoroughly.
- Rare diagnoses
- Klinefelter syndrome: A genetic condition (47,XXY) associated with gynecomastia, among other features. However, this would typically be accompanied by other signs such as small testes, which is not the case here.
- Adrenal or pituitary tumors: These can cause hormonal imbalances leading to gynecomastia. They are rare and would likely be associated with other systemic symptoms or signs of hormonal excess.