Management of Oval‑Shaped Masses in Very Dense Breasts

Imaging Assessment and Predictive Value

The American College of Radiology (ACR) notes that an oval‑shaped mass on mammography in extremely dense breasts strongly suggests a benign lesion, with the majority representing fibroadenomas; however, ultrasound correlation is required for definitive characterization and to exclude malignancy. 1
According to the ACR Appropriateness Criteria, round or oval circumscribed masses are classified as “probably benign” findings and should be evaluated with ultrasound rather than proceeding directly to biopsy. 1

Ultrasound is mandatory for further characterization of oval masses in dense breasts because mammography alone has reduced sensitivity in this population. 1
Benign ultrasound features (indicating a likely benign lesion): simple cyst, or solid mass that is oval, has circumscribed margins, homogeneous echogenicity, a parallel orientation to the chest wall, and lacks posterior acoustic shadowing. 1
Suspicious ultrasound features (prompting biopsy): irregular shape, microlobulated or spiculated margins, non‑parallel orientation, and posterior acoustic shadowing. 1

A short‑interval follow‑up (6 months) is appropriate when mammography, ultrasound, and clinical examination all suggest a benign etiology. 1
The incidence of cancer in properly characterized “probably benign” masses is only 0–2 % . 1

The mass is new on imaging. 1
The mass is enlarging (≥ 20 % increase in volume or diameter over a 6‑month interval). 1
The patient is high‑risk (e.g., awaiting organ transplant, has a synchronous cancer, or is planning pregnancy). 4

Strict application of the BI‑RADS lexicon to “probably benign” masses yields very low cancer rates, underscoring the importance of standardized terminology. 1
Definitive correlation between mammographic and sonographic findings is essential before opting for surveillance rather than biopsy. 1

A parallel orientation of the lesion to the chest wall on ultrasound favors a benign etiology. 1