Some of the cysts contain reflective material and are surrounded by hyperechoic inflamed fat which can not be differentiated from the desmoplastic reaction as can be seen in malignancy.
In this case no malignancy was found.
For more forms of malignant breast lesions see category
Günhan-Bilgen I, Memis A, Ustün EE, Zekioglu O, Ozdemir N Metaplastic carcinoma of the breast: clinical, mammographic, and sonographic findings with histopathologic correlation.AJR Am J Roentgenol. 2002 Jun;178(6):1421-5.
Park JM, Han BK, Moon WK, Choe YH, Ahn SH, Gong G. Metaplastic carcinoma of the breast: mammographic and sonographic findings.
J Clin Ultrasound. 2000 May;28(4):179-86.