Differential Diagnosis for Unilateral Breast Discharge Serous

• Single Most Likely Diagnosis
  • Intraductal Papilloma: This is the most common cause of unilateral, serous, or bloody nipple discharge. It is a benign tumor that grows in the milk ducts of the breast. The discharge is often spontaneous and from a single duct.
• Other Likely Diagnoses
  • Ductal Ectasia: This condition involves the widening of a milk duct in the breast, which can cause a serous or greenish discharge. It's more common in older women and can be associated with periductal mastitis.
  • Breast Abscess or Infection: An infection of the breast tissue can cause a serous or purulent discharge, especially if the infection involves a duct.
  • Fibrocystic Changes: While more commonly associated with bilateral, multiple duct discharge, fibrocystic changes can occasionally cause a unilateral serous discharge.
• Do Not Miss Diagnoses
  • Breast Cancer (Ductal Carcinoma In Situ or Invasive): Although less common, breast cancer can present with unilateral, serous, or bloody nipple discharge. It's crucial to investigate any new or persistent discharge, especially in the presence of other symptoms like a lump.
  • Pituitary Tumor (Prolactinoma): A prolactinoma can cause an increase in prolactin levels, leading to galactorrhea, which is a milky discharge not associated with childbirth or nursing. However, in some cases, the discharge can be serous, especially if the tumor affects other hormonal balances.
• Rare Diagnoses
  • Syringomatous Adenoma of the Nipple: A rare, benign tumor of the nipple that can cause a serous or bloody discharge.
  • Paget's Disease of the Breast: A rare form of breast cancer that affects the skin of the nipple and, sometimes, the areola. It can cause a serous discharge, along with other symptoms like itching, redness, and a rash.