Imaging features of sporadic breast cancer in women under 40 years old: 97 cases.

Objectives: To evaluate characteristic features of mammography, ultrasound and magnetic resonance imaging (MRI) of sporadic breast cancer in women <40 years and to determine correlations with pathological and biological factors.

Methods: A retrospective review of radiological, clinicopathological and biological features of sporadic breast cancers for women under 40 years at our institution between 2007-2012 covering 91 patients. Mammography was available for 97 lesions, ultrasound for 94 and MRI for 38.

Results: The most common imaging features were masses, nearly all classified BI-RADS 4 or 5. On mammography microcalcifications alone accounted for 31 %, all suspicious. There were 42.6 % luminal B, 24.5 % luminal A, 19.1 % HER2-enriched and 10.6 % triple-negative (TN) tumours by immunohistochemistry. HER2 overexpression was correlated with the presence of calcifications at mammography (P = 0.03). TN cancers more often had an oval shape and abrupt interface at ultrasound and rim enhancement on MRI. MRI features were suspicious for all cancers and rim enhancement of a mass was a significant predictor of triple-negative tumours (P = 0.01).

Conclusions: The imaging characteristics of cancers in patients under 40 years without proven gene mutations do not differ from their older counterparts, but appear correlated to phenotypic profiles, which have a different distribution in young women compared to the general population.