Malignant lesions on digital Mammography show irregular, speculated and dense opacities with or without microcalcifications those on HR-USG appear ill defined irregular, ragged, microlobulated and hypoechoic masses with posterior shadowing and may show 1–3 mm calcifications [17]. Most of malignant lesions show different patterns of central, tortuous and penetrating vascularity on Doppler Flow. Malignancy is confirmed on histopathology of Trucut biopsies. We opted for Trucut biopsy in all lesions with irregular or micro lobulated margins (Fig. 3).
Phyllodes tumor shows features of benign tumor with well-defined regular margins but larger in size with history of rapid growth and may show cystic areas and moderate vascularity on Doppler scan (not shown).
Benign lesions have more or less same incidence in both age groups with Fibroadenoma being the most common benign lesion in the younger age group and cysts in older age groups. Fibroadenoma is common in younger women and is characterized on HR-USG as well defined with smooth margins usually hypoechoic, parallel to skin surface and wider than taller mass which may show posterior enhancement or macrocalcifications. Higher risk of transformation in breast cancer is seen in complex Fibroadenomas those might appear as lobulated, might show calcifications or cystic changes. These patients are put on close follow-up for any change in size or shape so might be further evaluated by Pathological correlation [18, 19]. Our study elaborated the commensurate frequency of benign lesions in both age groups. Fibroadenoma was the most common benign lesion in our patients of all age groups.
Cysts are common in older age groups. Cysts may appear simple or complex on HR-USG. Simple cysts appear as well defined thin walled anechoic lesion and does not show vascularity while complex cyst might show thick or irregular wall, mural nodularity, internal echoes or intracystic solid component [11]. Complex cysts may show malignancy on histopathology so should be evaluated on aspiration cytology or biopsy of solid component or cyst wall (not shown).
Lipoma appears on HR-USG as well defined, superficially located in subcutaneous tissue, and is usually isoechoic but can appear Hyperechoic or Hypoechoic as well [20]. Our study showed Lipoma was one of the common benign lesions after Fibroadenoma seen in all age groups (not shown).
Galactocele is common finding in lactating mothers or in mothers who have recently stopped lactations. Blockage of milk duct is the main cause of Galactocele. Our patients presented with lumps during lactation. These on HR-USG appear as large commonly loculated or even complex cysts with moving echoes in it. Aspiration of milk confirms it (not shown).
Intraductal papilloma usually appears as well-defined echogenic lesions with smooth margins with in dilated duct or tubular cystic lesions. The common location for it is retroareolar region. The most of the patients presenting with nipple discharge or palpable retroareolar lump turn out to be intraductal papilloma or carcinoma [21]. On USG it is difficult to differentiate between papilloma and carcinoma. It is only confirmed on FNAC or Biopsy (Fig. 4).
Inflammatory lesion is common in lactating women. Acute abscess present with fever, painful lump with skin redness and edema. Inflammatory lesion on Mammography is challenging for a Radiologist to differentiate from malignant lesion and appears as ill-defined irregular/speculated dense opacity (Fig. 5). Its findings on mammography mimic those of suspicious or malignant lesion and are only differentiated on HR-USG that shows ill-defined large, complex, irregular cystic or heterogeneous lesion that may show fluid movement in it (Fig. 6). Aspiration of pus or FNAC/Trucut biopsy confirms inflammatory lesion.
Duct Ectasia is a benign condition seen most commonly in perimenopause age that occurs when a milk duct widens with thickening of its walls. This can cause the blockage of duct leading to fluid build-up. Common presentation is nipple discharge or lumpy feeling. HR USG reveals dilated ducts that are usually multiductal and bilateral [22].