Sternal Observations After Modified Radical Mastectomy
Modified radical mastectomy does not directly involve the sternum, as the procedure preserves the pectoralis major muscle and does not require sternal manipulation or resection. 1, 2
Key Anatomical Considerations
The modified radical mastectomy technique specifically preserves the pectoralis major muscle while removing breast tissue and performing axillary lymph node dissection. 1, 2 This differs fundamentally from procedures requiring sternotomy or chest wall resection, where sternal changes would be expected. 3
When Sternal Changes May Occur
Sternal involvement after modified radical mastectomy is pathological rather than procedural, occurring in the following scenarios:
Local-Regional Recurrence
- Chest wall recurrence can extend to involve parasternal structures and the sternum itself, presenting as enhancing soft tissue lesions at the sternal edge on MRI and PET-CT. 4
- Internal mammary lymph node recurrence may occur along the parasternal region, requiring imaging evaluation with CT to detect sternal proximity or involvement. 5
- Recurrence rates after mastectomy range from 1-2% per year, with local failure occurring at constant rates through years 2-8 post-treatment. 3, 6
Imaging Findings in Recurrent Disease
- MRI with T1-weighted fat-suppressed sequences after gadolinium is superior to CT for detecting residual or recurrent tumor involving chest wall structures including parasternal areas. 3
- PET-CT demonstrates high sensitivity (91%) and specificity (97%) for detecting sternal involvement when infection or tumor recurrence is suspected. 3
- Enhanced lymph nodes at the sternal edge on imaging warrant tissue diagnosis to exclude metastatic disease. 4
Common Post-Mastectomy Findings (Non-Sternal)
The most common postoperative findings are soft tissue changes rather than bony abnormalities:
- Fat necrosis is the most frequent early postoperative finding, presenting as palpable masses that must be distinguished from recurrence. 6, 7
- Late seromas can develop and require ultrasound-guided aspiration with cytologic evaluation to exclude malignancy. 6
- Chest wall pain may occur but is related to soft tissue healing rather than sternal pathology. 2
Critical Diagnostic Pitfall
Never assume any palpable abnormality or imaging finding near the sternum is benign without tissue diagnosis, as local recurrence can manifest in subcutaneous tissue, deep to the pectoralis muscle, or along parasternal structures. 6, 7 Ultrasound should be the initial imaging modality for any palpable mass in the post-mastectomy setting. 7