Mammo & Ultrasound Results Worry Me

Hi, I am 39 years old; have no known family hx of breast or any other cancer and have been categorized on my radiology exam report from 5/2010 as left breast BIRADS 4.  This US exam was performed after a CBE with my OB and my first bilateral mammo.  

The report states that my breasts are "heterogeneously dense".  Also that: "Multiple foci of asymmetric densities are noted bilaterally some of which are partly well circumscribed.  There is a dominant poorly circumscribed asymmetric lesion in the deep central left breast."

With regard to this lesion it continues, describing it as "a solid hypoechoic microlobulated heterogenous lesion in the area of asymmetric lesions seen in the left breast.  The mass measures 2.5 x 1.4 x 1.8 cm and is located at the 11:00 position.  There is mild posterior shadowing."  

The final impression reads as follows:  "Solid microlobulated mass with poorly circumscribed borders in the central left breast at the 11:00 position.  A sonographically guided core needle biopsy is suggested."

Within the report it is noted also that for my left breast "There is no clear evidence of architectural distortion.  No suspicious microcalcification groupings are seen.  There is no skin thickening or nipple retraction."

My physician is referring me to a general surgeon for evaluation, biopsy and/or surgical extraction.  This whole situation worries me.

I wish to understand the meaning of:  "microlobulated" , "heterogenous" , "hypoechoic" , "heterogenity".  Also what is "architectural distortion" and "microcalcification" ?

My physician mentioned that 2.5 cm is a rather large lesion.  Are lesion measurements given in these reports length x width x depth?   Also, is lesion size an indicator of malignancy?

Thanks for any information.

[Cleveland Clinic]

Dear Zuno, When the radiologist is looking at the films they are looking for abnormalities.  Certain findings are more suspicious than others.  All of these terms are descriptors of the lesion (definitions of each term individualy is just giving a description of the lesion).  What's important is that put together in context these features add up to something that is suspicious and requires further evaluation.  

[Zuno]

Also, what is "shadowing" and why is it bad?

Thanks.