Imaging features of pure mucinous breast carcinoma: correlation with extracellular mucus content

Abstract

To analyse the correlation between imaging features using multiple techniques and extracellular mucus content in pure mucinous breast carcinoma (PMBC). A retrospective review of available images from 25 patients with 25 PMBC tumours was conducted, with ultrasonography (US), ultrasonic elastography (USE), mammography, and breast-specific gamma imaging (BSGI) available for 25, 15, 11, and eight patients, respectively. Microscopic slides from each tumour were evaluated for extracellular mucus content. The correlation between imaging features and mucus content was analysed using linear-by-linear association chi-square tests or Spearman's rank correlation analyses. On US images, a significant correlation was found between mucus content and echo pattern (p=0.042) and colour Doppler blood flow (p=0.032), with a trend that the lower mucus content present in tumours, the more likely they were detected with isoechoic echo and high blood flow. On USE images, a moderate negative correlation (r=-0.60, p=0.029) was observed between mucus content and tumour stiffness. On BSGI images, a strong negative correlation (r=-0.92, p=0.001) was shown between mucus content and lesion to non-lesion ratio (L/N) values of radioactivity counts. No significant correlation was found between mucus content and mammography imaging features (all p>0.05). Imaging features at US, USE, and BSGI correlated with extracellular mucus content in PMBC tumours, among which the L/N value using BSGI imaging is the most relevant feature.