Analysis of patients with false negative mammography and symptomatic breast carcinoma.

Aim: False-negative mammograms may result in a delay in breast carcinoma diagnosis and have important implications for patient care. In this study, the characteristics of symptomatic patients with false-negative mammograms were analysed.

Methods: Patients with symptomatic breast carcinoma were identified over a 10-year period (1994-2004). One hundred and twenty-four patients had false-negative preoperative mammograms and 1241 patients had abnormal preoperative mammograms. Clinical presentation, diagnostic methods and pathology were analysed. False-negative mammograms were reviewed by a specialist breast radiologist.

Results: Following retrospective review, 42% of false-negative mammograms were re-categorised as suspicious. The most commonly misinterpreted lesion was architectural distortion/asymmetrical density. Adjuvant ultrasound, where performed (n = 27), raised the level of suspicion in 93% of cases. Patients with false-negative mammograms were more likely to be younger (P < 0.0001), present with nipple discharge (P = 0.002) and have smaller tumours (P < 0.0001). Their tumours were more frequently located outside the upper outer quadrant (P = 0.002). False-negative mammography led to a delay in diagnosis of >2 months in 12 patients.

Conclusion: Symptomatic patients with false-negative mammograms often demonstrate definite abnormalities on imaging, the most common of which is architectural distortion/asymmetrical density. Those at particular risk were younger patients, those with nipple discharge, and patients with lesions located outside the upper outer quadrant.