Use of contrast-enhanced mammography for the diagnosis and staging of invasive lobular breast cancer.

OBJECTIVE: To evaluate the accuracy of contrast-enhanced mammography (CEM) in the diagnosis and local staging of invasive lobular carcinoma (ILC) of the breast. MATERIALS AND METHODS: A single-centre retrospective study was conducted between September 2019 and June 2024, including patients with a histological diagnosis of pure invasive lobular carcinoma (ILC) who underwent primary surgery and contrast-enhanced mammography (CEM) as part of preoperative planning. Tumour characteristics and multifocality were analysed using conventional mammography, CEM and breast magnetic resonance imaging (MRI) when available. Diagnostic accuracy was analysed based on the detection rates of the imaging techniques. Local staging was evaluated by comparing the preoperative tumour size and presence of multifocality with the pathological findings. RESULTS: A total of 16 patients with pure ILC were included. Conventional mammography detected the tumour in only 56.2% of cases (9/16). CEM detected 100% of ILCs, and MRI detected 100% of the cases evaluated (14/14). Accuracy in tumour size assessment among detected cases showed mean tumour sizes of 13.87 mm with conventional mammography, 36.06 mm with CEM, and 38.71 mm with MRI, compared to 35.1 mm on pathological examination. A statistically significant difference was observed between tumour size measurements by conventional mammography and the histological size (P = .0075). No statistically significant differences were found between tumour sizes measured by CEM (P = .85) or MRI (P = .75) and histological size. CEM demonstrated a higher detection rate of multifocality compared to conventional mammography, and a rate similar to that of MRI. CONCLUSIONS: CEM is an emerging radiological technique that has shown high accuracy for the diagnosis and staging of ILC of the breast, with a diagnostic performance comparable to that of MRI.