[Diagnostic difficulties and limits in imaging].

Fine-needle cytology and core biopsy of the breast done under mammographic or ultrasonographic guidance can assist in decision-making (monitoring, diagnostic or therapeutic procedures). Cytologic studies and histologic evaluation of core biopsies have their own limitations: the samples are small in size, and the histopathological features of the lesions are often complex. Each step of an image-guided diagnostic procedure contributes to the reliability of the method. The characteristics of the mammogram and/or ultrasonogram image provide initial orientation. Whether they are concordant with the results of the cytologic or histologic study is an important factor. The main limitations of stereotactically-guided biopsies are ballistic with targets that are difficult to circumscribe (fine microcalcifications or ill-defined density). With ultrasonography, verification of the sampling site in the target is essential. The performances of these procedures are closely dependent on the experience of the operators and on the quality of the cooperation between clinicians, radiologists and pathologists.