Ultrasound characteristics of breast fibromas depend on age and tumour size

Objectives: Fibromas are the most frequent benign tumours of the breast. We hypothesised that ultrasound characteristics of these tumours are related to patient's age and to tumour size.

Methods: 11 ultrasound characteristics which are frequently observed in breast tumours were defined in detail before the onset of our study (shape, tumour axis, echogenicity, margin contour, margin shape, internal structure, calcifications, posterior and lateral ultrasound transmission, surrounding tissue). These characteristics were analysed in a retrospective study on thermoprint images of 280 fibromas from 280 patients. The relation between the observed ultrasound characteristics and age and the maximum tumour diameter were analysed using Pearsons chi-square test. Therefore, age and tumour diameter were categorized into four groups according to the 25%, 50% and 75% percentiles of the study population.

Results: Median patient's age was 41 years and median maximal tumour diameter was 16mm. Younger patients had bigger tumours than older patients (p<0,001). Tumour margin characteristics and posterior ultrasound transmission were related to age. Older subjects had more often tumours with an irregular tumour margin and with a posterior shadowing and less often posterior ultrasound amplification (p<0,001). Bigger tumours had more frequently a horizontal tumour axis (p=0,04), a lobulated margin (p=0,002), an inhomogeneous internal echo pattern (p<0,001), calcifications (p=0,003) and a posterior ultrasound amplification (p<0,001).

Conclusions: Ultrasound characteristics of fibromas are related to tumour size and to age. This has to be considered when tumours are classified and when decisions for biopsies are made.