Ultrasonography, Breast, Cancer, Superficial fascia
Seventy five patients with histologically proven breast tumors were studied retrospectively to evaluate ultrasonographic delineation of the superficial layer (SL) of the superficial fascia adjacent to the tumor. Patients were laid on the back with a water-bag placed on the breast. Ultrasonography was performed using an electronic-linear scanner with a probe of 5.0 MHz. When the SL was identified over the tumors, it was classified into 3 types according to morphological changes in shape in the vicinity of the tumor; flat, disrupted, and convergent type. Additionally, SL and adjacent stroma were studied from histological and biological view-points. SL was identified ultrasonographically in 65 patients (82%). Among them, 27 were evaluated to be of the flat type, and 23 (85%) of these had benign tumors. The remaining 38 were subdivided into distrupted or convergent types, and 35 (92%) had cancerous lesions. In breast cancer, histological study revealed that SL was retracted toward the lesion through the Cooper's ligament, which was thickened, shortened, and sometimes invaded by cancer cells. Tissue culture of the peri-tumoral stroma showed marked growth of fibroblast-like cells. Meanwhile, little proliferation was noticed from normal breast gland separate from the cancer. The present study suggested that ultrasonographically disrupted or convergent SL reflects histological retraction due to the stromal reactive changes of breast cancer. Thus, ultrasongraphic evaluation of the SL can be a useful clue in differentiating cancerous from benign lesions.