Mammographic signs of malignancy
On mammograms, breast cancer can present differently depending on the histological type.
- Ill-defined masses (ill-defined mass) and spiculated structures (spiculated masses) are classic signs of malignancy (e.g., in invasive carcinoma, tubular, and cribriform carcinoma).
- Architectural distortion and an abnormal trabecular pattern are frequent findings.
- Microcalcifications (microcalcifications) are clearly distinguishable even against dense tissue background. Their presence, especially as segmental clusters of pleomorphic forms (granular, branching), is characteristic of high-grade ductal carcinoma in situ (DCIS).
Special cases:
- Papillary, mucinous, and medullary cancers may have well-defined margins and a lobulated structure, mimicking benign tumors.
- Inflammatory breast cancer (an aggressive form clinically manifesting with the "peau d'orange" sign) shows skin and trabecular thickening on X-ray.
Ultrasonic semiotics
Ultrasound effectively complements mammography, especially for evaluating dense breasts and local staging.
Typical US signs of malignancy:
- Shape and margins: ill-defined margins, irregular shape.
- Echogenicity: pronounced hypoechogenicity compared to the surrounding adipose tissue.
- Orientation: vertical ("taller than wide") — anteroposterior dimension exceeds transverse.
- Acoustic effects: presence of posterior acoustic shadowing (posterior acoustic shadowing) due to high tissue density.
- Rim: an ill-defined echogenic halo (echogenic halo) at the periphery.
On Doppler imaging, malignant tumors often reveal abnormal vessels penetrating into the center of the mass, while elastography detects zones of increased stiffness whose boundaries exceed those visible in grayscale mode.
Important: poorly differentiated tumors (high-grade) may lack acoustic shadowing and have well-defined margins.
Differential diagnosis and calcifications
Analysis of calcifications on mammograms plays a decisive role in differential diagnosis.
| Type of changes | Calcification pattern | Characteristic |
|---|---|---|
| Fat necrosis | Eggshell | Large, ring-like with a radiolucent center |
| Fibroadenoma | Popcorn-like | Dense, large, lobulated (during involution) |
| Indeterminate | Small clusters | Require stereotactic biopsy for clarification |
| DCIS (carcinoma in situ) | Pleomorphic, segmental | Granular, rod-like, branching along the ducts |
Many suspicious areas on images may turn out to be summation artifacts of normal tissue. Cone-down compression views or tomosynthesis are used for clarification.
Lymph node assessment
Ultrasound is a key method for preoperative axillary staging, allowing the assessment of lymph nodes (LNs).
Signs of LN involvement:
- The ratio of longitudinal to transverse dimension becomes less than 2 (the node acquires a rounded rather than oval shape).
- The cortical thickness exceeds 3 mm, even if the overall shape of the node is preserved.
Suspicious nodes are sampled (ultrasound-guided biopsy). This confirms the diagnosis before surgery in more than 40% of patients and avoids total lymph node dissection in low-risk patients, reducing the likelihood of disabling lymphedema.
Briefly: answers to topical questions
What are the radiological differences between radial scar and invasive carcinoma?
- Radial scars (radial scars / complex sclerosing lesions) form spiculated lesions indistinguishable from malignant ones on mammography and ultrasound, are often asymptomatic, and are detected during screening.
- Invasive carcinoma (invasive carcinoma) is characterized by ill-defined margins and spiculated masses (spiculate masses), an abnormal trabecular pattern, and microcalcifications.
What are the TNM stages for breast cancer?
Breast cancer staging uses the TNM-8 (UICC) classification, which includes clinical and pathomorphological staging. The main categories are:
- T (Tumor) — primary tumor (Tis, T1, T2, T3, T4).
- N (Node) — regional lymph nodes on the affected side (N1, N2, N3).
- M (Metastasis) — distant metastases (M1).
Class and exam questions
What is the main difference between malignant and benign lesions on ultrasound?
Malignant tumors typically show vertical orientation, hypoechogenicity, posterior acoustic shadowing, and an echogenic halo. Benign ones often have horizontal orientation and well-defined margins.
What to do if a lesion appears benign, but there is a mass effect?
In such cases, core-needle biopsy is mandatory, as some high-grade tumors can mimic benign masses.
How do calcifications appear in fat necrosis?
They have an eggshell appearance — large ring-like structures with a radiolucent center.
What else to study on this topic
- Features of the radiological presentation of inflammatory breast cancer
- The role of digital breast tomosynthesis (DBT) in the differential diagnosis of summation artifacts
- Ultrasound diagnostics of lobular carcinomas
- Indications for sentinel lymph node biopsy
- Application of elastography in the evaluation of breast lesions
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