Radiological Features of Breast Cancer in Women Aged 40 Years and Younger: A Retrospective Study from a Tertiary Hospital in Saudi Arabia

Background: Breast cancer diagnosed in women aged 40 years or younger is rare on a global scale but shows a notable clustering in Saudi Arabia. This younger cohort frequently has denser glandular tissue and more aggressive cancer biology, which complicates early detection for imaging specialists. Objective: Our aim was to characterize the imaging features of breast cancer in young Saudi women and to relate these findings to underlying tumor subtypes within a tertiary hospital environment. Methods: We conducted a retrospective review of imaging and corresponding histopathology from 150 women aged 40 years or younger who received a breast cancer diagnosis at our institution between 2019 and 2024. Data from mammography, ultrasound, and MRI studies were examined in conjunction with tumor subtype classification. Results: The average age at diagnosis was 35.2 years (±4.1); 72% of the cohort was staged at II or III. Dense breast tissue (ACR classification C or D) was present in 82% of any mammogram performed. Ultrasound typically displayed irregular hypoechoic lesions accompanied by posterior acoustic shadowing (69% of cases), while MRI demonstrated fast initial enhancement followed by washout kinetics in 62% of tumors. The subtypes identified were Luminal A (22%), Luminal B (28%), HER2-positive (24%), and triple-negative (26%). Conclusion: Breast cancer affects young women in Saudi Arabia at an alarming prevalence of advanced stages and aggressive histological variants. The prevalence of radiologically dense breast tissue in this population diminishes mammographic sensitivity, making ultrasound the preferred first-line imaging technique and underscoring the utility of MRI for diagnostic resolution in complicated cases.