Heterogeneity of triple-negative breast cancer: mammographic, US, and MR imaging features according to androgen receptor expression.

OBJECTIVE

Our aim was to determine whether triple-negative breast cancers (TNBCs) with and without androgen receptor (AR) expression have distinguishing imaging features on mammography, breast ultrasound (US), and magnetic resonance (MR) imaging.

METHODS

AR expression was assessed immunohistochemically in 125 patients with TNBC from a consecutive series of 1,086 operable invasive breast cancers. Two experienced radiologists blinded to clinicopathological findings reviewed all imaging studies in consensus using the BI-RADS lexicon. The imaging and pathological features of 33 AR-positive TNBCs were compared with those of 92 AR-negative TNBCs.

RESULTS

The presence of mammographic calcifications with or without a mass (p < 0.001), non-mass enhancement on MR imaging (p < 0.001), and masses with irregular shape or spiculated margins on US (p < 0.001 and p = 0.002) and MR imaging (p = 0.001 and p < 0.001) were significantly associated with AR-positive TNBC. Compared with AR-negative TNBC, AR-positive TNBC was more likely to have a ductal carcinoma in situ component (59.8% vs. 90.9%, p = 0.001) and low Ki-67 expression (30.4% vs. 51.5%, p = 0.030).

CONCLUSION

AR-positive and AR-negative TNBCs have different imaging features, and certain imaging findings can be useful to predict AR status in TNBC.

KEY POINTS

• Triple-negative breast cancers have distinguishing imaging features according to AR expression. • AR-positive TNBC is associated with calcifications, spiculated masses, and non-mass enhancement. • Multimodality imaging can help predict androgen receptor status in TNBC.