Our aim is to demonstrate that mucinous carcinoma of the breast has an unusually high ADC value on diffusion-weighted imaging (DWI) compared to other malignant lesions. It can be clearly differentiated from other types of breast cancer on the basis of ADC values.

The role of DWI is well established in characterisation of benign from malignant breast tumors on the basis of ADC values.The use of DWI allows information regarding tissue function as well as structure to be obtained [1]. Malignant tumors are characterized by high cellularity, causing restricted diffusion of water molecules and causing lower ADC values than benign lesions regardless of the b-value or the technical differences [2-5].Mucinous carcinomas of the breast are rare (1–4% primary breast cancers), more likely to occur in older patients and...

Case 1.BackgroundA 72 year old woman with previous invasive ductal carcinoma of the right breast 20 years ago, was treated by wide local excision and radiotherapy.She presented with a new lump in the lower inner aspect of the right breast adjacent to the previous malignancy.An ultrasound guided biopsy of the area failed to identify malignant cells and therefore an MRI was arranged.ImagingT1-W images demonstrate an irregular low signal intensity (SI) mass (figure 1) which displayed increased SI on T2-W imaging (figure 2).Post intravenous gadolinium* contrast...

Diffusion-weighted imaging can aid in the differentiation of benign from malignant tumours of the breast, with malignant lesions demonstrating low ADC values.The most notable exception is mucinous carcinoma. The radiologist should be aware of this anomaly when using the DWI sequence to avoid misdiagnosing this rare tumor.

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