The aim of this study is to determine the accuracy of the preoperative measurement of tumour size, by imaging modalities and whether they deviate from the postoperative pathological measurement in breast cancer.

Material and methods: retrospective study done at King Fahad Hospital of University. For two years 2014-2015 all breast cancer patients included studied by reviewing US which was reported by two radiologists and gross size reports by five pathologists. The correlation of ultrasound, with pathology was studied.

Results: 118 cases were collected from January 2014 to December 2015 with diagnosis of breast carcinoma. 36 patients were excluded from the study. Finally, a total of 82 were included in the analysis. Invasive ductal carcinoma

(IDC) found in 57 patients (69.5%), 44 patients (53.7%) underwent breast conserving surgeries. 46 patient (56.1%) found to be either over or underestimated by US or Pathology.

Conclusion: Despite the importance of accuracy of tumour size in management planning this study reflect marked discrepancy in sizes. More collaboration between radiologist and pathologist will yield accurate measurement, which will impact positively on outcome.