What causes breast skin dimpling?

Causes of Breast Skin Dimpling

Breast skin dimpling is primarily caused by malignancy, specifically breast cancer that involves Cooper's ligaments, causing tethering of the skin without direct tumor invasion of the dermis.

Primary Causes

• Breast Cancer: The most common and significant cause of breast skin dimpling is breast cancer, particularly when the tumor involves Cooper's ligaments, causing tethering of the skin 1, 2
• Dimpling occurs when the tumor pulls on the Cooper's ligaments that connect the skin to the deeper breast tissue, creating a characteristic indentation 2
• This skin change can occur even when there is normal fat between the tumor and skin, indicating it's not necessarily due to direct skin invasion 2

Clinical Significance

• Skin dimpling is considered a classical clinical feature of breast cancer and an important physical finding that requires immediate evaluation 3
• The dimpling may only be visible in certain positions, such as when the patient raises her arms, making it easy to miss during routine examination 3
• According to ESMO guidelines, skin changes including dimpling may occur in T1, T2, or T3 tumors without changing their classification 1
• Dimpling can be an early sign of malignancy, as demonstrated by the "pushing sign" where pushing the lump in different directions elicits skin dimpling not otherwise evident 2

Other Potential Causes

• Benign Breast Disease: Some benign conditions can occasionally cause skin changes that mimic dimpling, though this is less common 4
• Post-surgical Changes: Scarring from previous breast surgeries can sometimes create tissue retraction that resembles dimpling 5
• Trauma: Significant breast trauma with subsequent fat necrosis and scarring can potentially cause skin retraction 5

Diagnostic Approach

• Any patient presenting with breast skin dimpling should undergo:
  • Bilateral diagnostic mammogram with or without ultrasound imaging 1
  • If imaging findings are classified as BI-RADS 4 or 5 (suspicious or highly suggestive of malignancy), tissue biopsy is recommended 1
  • Even with normal imaging (BI-RADS 1-3), further evaluation is warranted due to the high association with malignancy 1

Clinical Pearls and Pitfalls

• Important Pitfall: Skin dimpling may be subtle and only visible during certain maneuvers, such as raising the arms or pushing the breast tissue in specific directions 2, 3
• Skin dimpling should not be confused with inflammatory breast cancer, which presents with diffuse erythema and edema (peau d'orange) involving a third or more of the breast skin 1
• Dimpling can be present even in early-stage breast cancers and should never be dismissed as a normal finding 2
• Breast cancers presenting with skin changes (including dimpling) tend to be more aggressive than screen-detected cancers and often have a poorer prognosis 1

Associated Findings

• Other concerning findings that may accompany skin dimpling include:
  • Palpable mass 1, 6
  • Nipple retraction 1
  • Asymmetric thickening of breast tissue 1
  • Skin thickening (normal range is 0.5-2.7 mm; >2.5 mm suggests disease) 5

Remember that skin dimpling, even when subtle or intermittently visible, requires thorough evaluation as it is strongly associated with underlying malignancy and may represent an early opportunity for diagnosis 2, 3.