| Gynecomastia | 63 to 93 | Discrete, round, mobile mass under areola; usually bilateral |
| Pseudogynecomastia | 5.4 | Increased adipose rather than glandular tissue on examination |
| Breast cancer | 1.4 to 2.9 | Patient falls outside of age range for physiologic gynecomastia |
| Bloody nipple discharge |
| Axillary lymphadenopathy |
| Nonpainful mass (pain more common in gynecomastia) |
| Often unilateral |
| Personal history of malignancy |
| Lipoma | 0.9 to 2.9 | Asymmetric breast enlargement |
| Sebaceous cyst | 1.4 to 2 | Drainage of material from site |
| Swelling feels closer to skin than a part of deeper tissue |
| Asymmetric breast enlargement |
| Mastitis | 0.8 to 1.1 | Systemic signs of infection |
| Fat necrosis | 0.3 to 0.9 | History of injury to the area may be present |
| May be a local swelling, not over nipple areolar complex |
| Asymmetric breast enlargement |
| Dermoid cyst | 0.9 | Painless lump that may enlarge; |
| may be anywhere in the breast |
| Hematoma | 0.9 | History of injury to the area may be present |
| Asymmetric breast enlargement |
| Metastatic disease | 0.8 | History of cancer |
| Ductal ectasia | 0.5 | Nonspecific breast tenderness |
| Hamartoma | 0.5 | Solid mass; diagnosis made with pathologic examination |
| Lymphoplasmacytic inflammation | 0.5 | Diagnosis made on pathology specimen after removal of mass |
| Postsurgical changes | 0.5 | History of surgery |
