Population screening detected non-lymphomatous non-mammary metastases to the breast. A radiology multimodality pictorial essay

This pictorial essay is a presentation of imaging appearances of non-mammary cancer metastases to the breast detected in asymptomatic women attending BreastScreen Western Australia (BSWA) from 2005 to 2019. Haematological malignancies were excluded. Thirteen cases of histologically proven extramammary metastases to breast were identified from the BSWA data base. Five cases were ovarian cancer metastases, 3 melanoma metastases, 2 of adenocarcinoma metastases with foregut primary and one each of endometrial, renal and carcinoid metastases. Metastasis to breast commonly presented as circumscribed masses (N = 12) at mammography and as hypoechoic masses (N = 10) at ultrasound with a predilection to upper outer quadrant of breast. Metastases to breast from non-mammary primary while a rare occurrence in a breast screening program, may be the first clinical presentation of malignancy in asymptomatic women.