Sikandar Mohd Shaikh DMRD, Presenter: Nothing to Disclose

To assess the prevalence of cancer in patients with breast lesions Oof ≤5mm in size by MRI and to identify MRI characteristics that are related to malignancy.

We retrospectively reviewed data of 27 patients with 28 MRI-detected suspicious breast lesions ≤5mm in size who underwent MRI localization and surgical biopsy at our institution .Indications for MRI of the breast included high risk screening (n=5), suspicious clinical findings (n=6), indeterminate findings on conventional imaging (n=6), and staging of known breast cancer (n=10). Breast lesion morphology and enhancement kinetics were scored and categorized according to the ACR BI-RADS-MRI lexicon criteria. In all cases MRI findings were correlated with pathology.

Size of 28 breast lesions on MRI varied from 2 to 5mm. Analysis of lesion morphology according to the BI-RADS-MRI lexicon criteria revealed oval smooth margins in 13 (46%), round smooth margins in 10 (37%), irregular margins in 2 (8%), lobulated margins in 1(5%), and spiculated margins in 1 (4%) cases. Kinetic enhancement curves of the 28 lesions were coded as benign in 5 (18%), indeterminate in 7 (25%), and suspicious in 12 (44%) cases, in 4(13%) lesions curve analysis was not possible due to their small size. Histopathologic analysis showed 9/28 malignancies (33%). The other 19 lesions proved to be 3 high risk lesions and 16 benign lesions. Although, no morphologic features significantly differentiated between benign and malignant small breast lesions, all 9 malignancies presented with abnormal enhancement kinetics, i.e. indeterminate in 3 or suspicious in 5 (in 1 lesions analysis of enhancement kinetics was not possible due to small size).

 MRI-detected breast lesions ≤5mm as malignant was 33%. Our findings indicated the importance of kinetic enhancement curves analysis when evaluating small ≤5mm breast lesions on MRI, since all malignancies presented with abnormal enhancement kinetics.

 MRI-detected breast small breast lesions in which biopsy was warranted.

Shaikh, S, Breast Lesions of 5mm or Less in Size: Role of MRI.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6009063.html