Differential Diagnosis for Sudden Swelling of the Right Breast

Single Most Likely Diagnosis

• Breast cyst: A breast cyst is a fluid-filled sac that can cause sudden swelling, especially if it becomes large or ruptures. It's a common condition, often asymptomatic, but can cause discomfort or pain.

Other Likely Diagnoses

• Breast abscess: An infection of the breast tissue that can cause swelling, redness, and pain. It's more common in lactating women but can occur in anyone.
• Trauma or hematoma: A bruise or collection of blood in the breast tissue, which can cause swelling and pain after an injury.
• Mastitis: Inflammation of the breast tissue, often caused by infection, which can cause swelling, redness, and pain.

Do Not Miss Diagnoses

• Breast cancer with inflammatory presentation: A rare but aggressive form of breast cancer that can cause sudden swelling, redness, and warmth of the breast. It's essential to rule out this diagnosis due to its poor prognosis if left untreated.
• Deep vein thrombosis (DVT) or Mondor's disease: A blood clot in the deep veins of the breast or a thrombophlebitis of the superficial veins, which can cause swelling, pain, and warmth.

Rare Diagnoses

• Galactocele: A milk-filled cyst that can cause swelling, often in lactating women.
• Fat necrosis: A condition where the breast fat tissue dies, often after trauma, which can cause swelling, pain, and a palpable mass.
• Lymphatic obstruction: A blockage of the lymphatic vessels, which can cause swelling of the breast, often due to surgery, radiation, or infection.