To value LCNB accuracy in the determination of morphobiological parameters and as an alternative to the open SB diagnostic procedure of breast lesions.University Hospital, Italy.From May 1992 to February 1995 196 biopsies have been performed. The diameter of the neoplasms examined varied from 0.6 to 7 cm with an average of 1.9 cm.The accuracy of the two methods in the evaluation of histological degree, receptor state, protein c-erb B2 and p53 were compared.No inadequate sampling were ever recorded. LCNB has shown values of 97% sensitivity and 100% specificity. The positivity and negativity predicted values obtained were 100% and 89% respectively. Retrospectively 70 sample-cases of carcinoma were selected and the morphobiological parameters evaluated. The correlation coefficients for the data obtained with SB and LCNB in the evaluation of Progesteron and Oestrogen receptor expression, protein c-erb B2 and p53 were excellent. Furthermore it was noted that LCNB allows a saving of at least 1/3 of the cost vs intraoperative SB.Percutaneous LCNB has high diagnostic accuracy for histological classification. LCNB has the same accuracy as SB for morphobiological parameters. The cost of LCNB is markedly lower than SB.