[Invasive lobular breast cancer: pitfall for the radiologist?]

Invasive lobular carcinoma accounts for 5-10% of all breast cancers and is associated with subtle clinical and mammographic changes. It is also frequently multifocal and traditional diagnostic methods are unable to reliably detect this preoperatively. The aim of the study was to evaluate the ability of current imaging modalities to detect and analyze invasive lobular carcinomas as compared to invasive ductal carcinomas.

A retrospective analysis of 396 invasive carcinomas - 331 ductal (84%) and 65 lobular (16%) - between 2000 and 2002 was performed. The two group were compared on the basis of result of mammography, physical examination, ultrasound, and cytology using a coded system points 1-5 concerning the malignancy.

The sensitivity of mammography and sonography for malignancy were higher in case of ductal carcinomas (81%, 77.4%), then by lobular cancers (75%, 72.2%), but the differences were not significant (p=0.4693 and p=0.4227 respectively). The radio-morphologic analysis shows the most frequent image was the stellate lesion in both group, but the difficult detectable structural distortions were found in 14.2% in lobular cancer- group, but only in 5.1% in case of ductal cancers without significance (p=0.5523). The clinical examination could predict the malignancy least of all, in the ductal group 42%, in the lobular group 40.2%. The cytology produced the best diagnostic result for malignancy in the ductal group 86.2%, and in the lobular group 76.5% was observed, the difference is significant (p=0.0069).

Although all elements of triplet diagnostics produces were more uncertain for malignancy in case of lobular carcinomas than ductal one, combining the result of the three radiological modalities and cytology increase the preoperative detection rate of lobular carcinoma.