Asymmetric breast tissue.

Abstract

A prospective study was undertaken to evaluate the significance of asymmetric breast tissue (asymmetric volume of breast tissue, asymmetrically dense breast tissue with preserved architecture, or asymmetrically prominent ducts) on mammograms. Of 8,408 mammograms obtained in 1985, 221 (3%) demonstrated asymmetric breast tissue. Follow-up was 36-42 months after the initial mammographic study. During this time none of the patients underwent biopsy on the basis of mammographic findings, although 20 underwent excisional biopsy because of clinical findings. Breast cancer was diagnosed in two patients and breast lymphoma in one patient. Biopsy specimens from the remaining 17 patients were benign. At mammography, all three malignant lesions had a palpable abnormality associated with the asymmetric tissue. Breast cancer was not found in any of the remaining 201 patients. Therefore, an asymmetric volume of breast tissue, asymmetrically dense breast tissue, or asymmetrically prominent ducts that do not form a mass, do not contain microcalcifications, or do not produce architectural distortion should be viewed with concern only when associated with a palpable asymmetry and are otherwise normal variations.

Optical mammography: bilateral breast symmetry in hemoglobin saturation maps

“…1,2 A study investigating breast density patterns on x-ray mammograms reported symmetry between 30 women's left and right breasts using both subjective and objective measurements schemes. 3 Subjective measures of symmetry were performed by radiologists grading the percentage of dense breast tissue in six categories (none, 0% to 10%, 10% to 25%, 25% to 50%, 50% to 75%, 75% to 100%) and comparing the grade given for right and left breast mammograms.…”

“…[4][5][6] However, when asymmetric appearance is found between right and left x-ray mammograms, it is considered to be a potential marker for cancer and it is carefully assessed by radiologists. In a study of over 8000 mammograms, it has been reported that only 3% of the cases were assessed by radiologists to have asymmetric breast tissue, 2 which indicates the high amount of similarity often seen between two breasts' mammographic appearances. This study did include asymptomatic and symptomatic women, however, any mammograms found with masses, microcalcifications, or architectural distortions were omitted from the analysis.…”

“…This study did include asymptomatic and symptomatic women, however, any mammograms found with masses, microcalcifications, or architectural distortions were omitted from the analysis. 2 Examining the symmetry in one breast over time is also performed in mammography and is used for identifying developing asymmetries. 7 Longitudinal comparisons with prior mammograms offer the advantage of looking at changes occurring within the same breast for screening and diagnostic purposes.…”

Asymmetric Mammographic Findings Based on the Fourth Edition of BI-RADS: Types, Evaluation, and Management

“…However, differences in imaging techniques and positioning, weight loss, hormone replacement therapy, or surgical procedures could cause global asymmetry. Occasionally, it may indicate the presence of an underlying breast cancer if it corresponds to a palpable abnormality (Fig 17) (12). In this clinical setting, the radiologist should recall the patient for additional imaging evaluation (Fig 7).…”

Conventional wisdom: observation, experience, anecdote, and science in breast imaging.

“…For example, the original suggestion that asymmetric breast tissue and asymmetrically prominent ducts were a secondary sign of malignancy was based on anecdote without regard to the denominator of these signs among " normal" women. For many years it was believed, on the basis of a few multicase reports, that these features were a secondary sign of malignancy, It was not until a prospective study was performed that it became apparent that asymmetric breast tissue, including asymmetrically prominent ducts, was a normal variation, and it was shown that the prevalence of breast cancer in women with asymmetric breast tissue was essentially no higher than the prevalence in women with symmetric breast tissue [1]. (Fig.…”