Imaging features of micropapillary DCIS: correlation with clinical and histopathological findings

The aim of this study was to describe the mammographic, sonographic, and magnetic resonance imaging (MRI) findings of micropapillary ductal carcinoma in situ.

Between May 2004 and April 2008, the pathology database of a single institution was reviewed for patients diagnosed with histologically proven DCIS with a predominant micropapillary component. Clinical data and preoperative imaging studies, including mammography, sonography, and/or MRI, were reviewed.

Forty-one patients (mean age, 55 years; range, 33-82 years) with 42 tumors were included in this study. Most tumors (n = 32 [76%]) were detected on screening mammography, with a mean tumor size of 4.7 cm (range, 0.5-13 cm). Of 42 tumors, seven (16%) were multicentric, and 23 (54%) were high nuclear grade. Calcifications were identified in 36 tumors (86%) on mammography, most frequently with pleomorphic morphology (15 tumors [42%]). Sonography was frequently normal (17 of 36 [47%]). When abnormal, irregular mass and angular margins were the most common sonographic features. All four tumors with MRI showed non-mass-like enhancement and showed the best correlation with pathologic size.

Micropapillary ductal carcinoma in situ is a unique subset of in situ cancer that is frequently clinically occult but has a large mean size at diagnosis and demonstrates highly suspicious features at imaging including pleomorphic calcifications on mammography and an irregular mass at sonography. MRI may be the imaging modality of choice for delineation of disease extent and warrants further validation.