Breast Lesion Characteristics and Diagnostic Approach

Imaging Characteristics

Malignant breast lesions appear as masses with irregular, spiculated, or indistinct margins on mammography and ultrasound, according to the American College of Radiology 1, 2
Malignant lesions often demonstrate heterogeneous internal echoes on ultrasound, as reported by the American College of Radiology 2
Benign lesions generally have well-circumscribed, oval or round shapes with parallel orientation to the chest wall, according to the American College of Radiology and the National Comprehensive Cancer Network 3, 5
Benign lesions typically demonstrate homogeneous internal echoes, as stated by the National Comprehensive Cancer Network 5

Malignant lesions exhibit nuclear pleomorphism and increased mitotic activity, as reported by Angiogenesis 7
Benign lesions can be classified into nonproliferative lesions, proliferative lesions without atypia, and proliferative lesions with atypia, according to the American College of Radiology 8

Malignant lesions most commonly present as a palpable mass, as reported by the American College of Radiology 3
The National Comprehensive Cancer Network recommends tissue diagnosis through core needle biopsy or surgical excision for malignant lesions 5, 9
Benign lesions may present as palpable masses or be detected incidentally on screening, and can be managed with observation if less than 2 cm and showing low clinical suspicion, as stated by the National Comprehensive Cancer Network 5, 6

The National Comprehensive Cancer Network recommends initial evaluation of suspicious breast lesions with mammography and ultrasound 5
The American College of Radiology prefers core needle biopsy over fine needle aspiration for tissue diagnosis 1
Concordance between pathology and imaging findings must be established, as reported by the National Comprehensive Cancer Network 5, 9
The American College of Radiology suggests considering MRI when other approaches fail to identify the underlying cause of suspicious findings 2