Ultrasonography for evaluation of breast lumps
There are some limitations of mammography as we have seen above. Next modality to evaluate breasts is ultrasonography. It is extremely important to characterise the lump felt or seen on mammography when it does not have classic features of cancer.
On USG, we basically differentiate whether the lump is solid or cystic.
Cystic lesions: Cysts may be present in many women and may not cause symptoms unless large. Simple cysts are non cancerous.
Solid lesions: Solid lesions can be cancerous or non cancerous. Ultrasound plays a major role in the differentiation of benign and malignant breast neoplasms in women aged 40 years or younger when mammography is less helpful due to dense breasts. Thus breast ultrasound is considered mandatory in the evaluation of the mammographically dense breast in all ages. The accuracy rate of ultrasound for palpable breast tumours has been reported as high as 95%.
Fibroadenoma is the most common solid lesion seen on USG. It may be diagnosed incidentally if small or may be palpated. This is estrogen dependent and usually involves as aging proceeds and women reaches menopausal state. Fibroadenomas are well defined homogenous hypoechoic lesions which tend to slip under ultrasound probe. These may be round or oval however are wider than taller. Certain findings like irregular shape, irregular margin, non-uniform distribution of internal echotexture , shadowing and calcifications in hypoechoic lesions are suggestive of cancer. Malignant lesions are usually taller than wider and may show small satellite nodules adjacent to lump.
Ultrasound also sees the axillary nodes that are involved by the cancer. These are lymph glands which are present in arm pit and are first to enlarge in case of breast cancer.