Assessment of factors affecting palpability of breast masses using ultrasonography in Chinese women

Five hundred and twenty-nine women with self-discovered or clinically palpable breast lumps had physical examination followed by high-resolution ultrasonographic examination of the breast. A total of 482 palpable and 146 nonpalpable masses were discovered by ultrasonography. The median values of the breast stromal, premammary, and retromammary fat thickness measurements were 1.3 cm, 0.1 cm, and 0.1 cm, respectively. The median depths of the lesions and the distance of the lesions from the pectoralis muscle were 0.5 cm and 0.2 cm, respectively. The median size of all breast masses was 1.5 cm. These measurements (of the tissue characteristics of the breast, location of the breast mass, and size of the breast lesion) were correlated with palpability or nonpalpability of the breast lesions. Multivariate logistic regression performed for all breast masses showed the only significant factors affecting palpability to be the size (anteroposterior and transverse diameters) and the depth of a breast mass. This is expressed by the following equation: formula: see text] where z = -0.8759 + 0.9691 (g) + 2.2770 (e)-1.5332 (d), and d represents depth of lesion from the cutaneous surface and e and g represent anteroposterior and transverse diameters of the breast mass, respectively. The nature of the breast tissue (i.e., the premammary fat, retromammary fat, or breast stromal thickness as determined by ultrasonography) does not affect palpability. This study would therefore strongly support the recommendation of breast self-examination, irrespective of breast structure.