Differential Diagnosis for a Lump in the Nipple of Young Men

Single Most Likely Diagnosis

• Gynecomastia: This is the most common cause of a lump in the nipple area in young men, often due to hormonal imbalance during puberty. It presents as a tender, palpable mass under the areola.

Other Likely Diagnoses

• Lipoma or Adipose Tissue: Benign growths of fat cells that can occur anywhere, including under the nipple.
• Cyst or Abscess: Fluid-filled lumps that can form under the nipple, sometimes infected and painful.
• Duct Ectasia: A condition where the milk ducts under the nipple become dilated, leading to a palpable mass.

Do Not Miss Diagnoses

• Breast Cancer: Although rare in young men, breast cancer can occur and must be considered, especially if there's a family history or other risk factors.
• Testicular Cancer Metastasis: Testicular cancer can metastasize to the breast tissue, presenting as a lump under the nipple.
• Inflammatory Breast Cancer: A rare and aggressive form of breast cancer that can cause a lump, redness, and swelling.

Rare Diagnoses

• Hamartoma: A benign growth made up of a mixture of tissues, which can occur under the nipple.
• Papilloma: A benign tumor that grows in the milk ducts of the breast, which can cause a lump under the nipple.
• Sarcoidosis: A condition that can cause lumps to form in various parts of the body, including under the nipple, due to granulomatous inflammation.