In situ and minimally invasive breast cancer : morphologic and kinetic features on contrast-enhanced MR imaging

Purpose: This retrospective study was under taken to investigate the morphologic and dynamic features of in situ and minimally inwlsive breast cancer on cont ras t -enhanced (c.-e.) MR imaging and to examine possible associat ions to pathology features. Material and methods: A total of 71 patients underwent MR imaging. Tl -weighted F L A S H 3 D images were obta ined before and after in t ravenous adminis t ra t ion of Gd-DTPA. Histopathologic analysis of 78 lesions revealed ductal carc inoma in situ (DCIS) n = 50 and DCIS with microinvasion n = 28. M R features were correlated with his topathologic tindings. Results: Enhancement in DCIS was focal (737~,), diffuse (10%) or ductal ([ 7"/,,). No enhancement occurred in two cases (4%). In 65% enhancement speed was classified as delayed. There was a tendency toward a more ill-defined (83 vs. 43%) enhancement pat tern in high grade DCIS and a more ductal (29 vs. 12%) and tipster (50 vs. 29%) enhancement in comedo type DCIS. However, significant differences in the enhancement behaviour could neither be demonst ra ted between high grade and non high grade DCIS nor between comedo and non comedo type DCIS. No signiticant differences were noted between pure and microinvasive DCIS. Conclusion: In this retrospective analysis the majori ty (96%) of DCIS lesions show cont ras t enhancement . However, in only about 50% of DCIS the criteria of a so-called "typical" enhancement behaviour was fulfilled, that means strong, early, focal ill-circumscribed or ductal. Enhancement that t\)llows a duct is often associated with malignancy, however this feature was only present in 17% of the cases. c.-e. MR imaging allowed the detection of 25 addi t ional foci of DCIS. Therefore mal ignant in situ lesions can be present with atypical enhancement , and should be taken into considerat ion in high-risk patients in particular. ¢O 2000 Elsevier Science B.V. All