Our study considered fourteen (14) patients with breast tumor which showed infiltration of the NAC; the patients were all candidates to neoadjuvant chemotherapy, thus they underwent MR, CT and PET/CT.

• We distinguished the pattern of enhancement at MR on the basis of the morphology and intensity. There were three types of morphology: SLE (smooth superficial enhancement) at the level of the skin, NEZ (zone without enhancement immediately below the SLE), INE (enhancement of the nipple below the NEZ but above the base of the nipple); INE pattern could be “linear” or “patchy” (patchy INE with round shape was better called “nodular”). On the basis of the intensity, enhancement could be minimal, mild, moderate, or marked.
• The pattern of enhancement at CT scans in the venous phase could be present or absent; it could involve the base of the nipple, the body of the nipple - or both.
• At ¹⁸FDG PET/CT images, we considered for quantitative analysis the maximum standardized uptake value (SUV) measured by delineating a three-dimensional volume of interest (VOI) over the NAC. The most representative image was selected, and the VOIs were drawn carefully not to include contiguous lesion areas. SUV values for the NAC in the malignant breast and the contralateral normal breast were obtained, and we then calculated the NAC-SUV ratio with the following formula: NAC-SUV = SUV of the NAC in the malignant breast / SUV of the NAC in the contralateral normal breast. The NAC-SUV was calculated for early phase images.