The benign signs for fibrocystic disease such as fibroadenoma and benign cyst are shown at the left; the malignant signs are shown at the right. In the high-sensitivity echograms (upper drawing) can be seen the tadpole-tail sign and the lateral shadow sign at the left, and the acoustic middle shadow sign at the right. In the low-sensitivity echograms (lower drawing) the length of the tadpole-tail sign becomes shortened and the tips of the lateral shadow signs gradually reach to the distal boundary echoes, and finally break into both sides of the distal boundary limits of lesion echoes, thus producing the bilateral disappearance characteristic of benign lesions. The acoustic middle shadow gradually increases toward the distal boundary limit of the lesion’s echoes and finally completely disappears as the sensitivity is gradually decreased. This sign is suggestive of malignant lesions. (From Cancer 33:940, 1974.) (Similar criteria modified schematically is cited and used by Prof. E. Pluygers, J. Belg. Radiol 58:15, 1975.)
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