Abstract
Neuroendocrine ductal carcinoma in situ of the breast（NE-DCIS）was recently recognized as a special subtype of DCIS, although the diagnostic criteria for NE-DCIS are yet to be established. DCIS is defined as the immunohistochemical expression of neuroendocrine markers chromogranin A and/or synaptophysin in over 50％ of tumor cells. Here, we investigated whether there are significant differences in magnetic resonance imaging（MRI）findings between NE-DCIS and non-NE-DCIS. The study sample comprised 8 lesions in 7 patients with breast NE-DCIS and 71 lesions in 69 patients with non-NE-DCIS who underwent preoperative MRI and histopathological diagnosis at our hospital from June 2010 to June 2012. The patients were females aged 34–85 years. We examined the lesion type, pattern of time-signal intensity curve（TIC）on dynamic contrast-enhanced MRI（DCE-MRI）, presence or absence of bloody duct ectasia delineation, and presence or absence of calcification on mammography（MMG）. Mass-type lesions were significantly more common in breast NE-DCIS than in non-NE-DCIS on MRI. On DCE-MRI, the TIC washout pattern was more commonly observed in NE-DCIS than in non-NE-DCIS, and although there was no significant difference in the rate of bloody duct ectasia delineation, it was relatively more common in NE-DCIS. MMG revealed a significant difference in calcification between non-NE-DCIS（60.1％）and NE-DCIS（0％）. Mass-type lesions and TIC washout pattern are significantly more common in patients with NE-DCIS than in those with non-NE-DCIS on MRI and DCE-MRI.
