Benign Breast Lesions That Mimic Cancer: Determining Radiologic-Pathologic Concordance

Julia Mario, BA; Shambhavi Venkataraman, MD; Vandana Dialani, MD; Priscilla J. Slanetz MD, MPH


Appl Radiol. 2015;44(9):28-32. 

In This Article

Inflammatory Conditions


Mastitis is a focal or diffuse breast infection, seen both in puerperal and non-puerperal states. Patients with acute mastitis typically present with tenderness, redness, swelling and warmth of the breast. Diagnosis is often made on clinical symptoms and response to antibiotics. Chronic mastitis, seen commonly in non-puerperal states, presents clinically with asymmetric breast thickening, breast lump, nipple discharge, and/or axillary lymphadenopathy without any constitutional symptoms.

Mammography may be difficult to perform due to tenderness and breast swelling and can be negative or show focal/diffuse skin thickening or an ill-defined focal asymmetry.[38] Sonography demonstrates skin thickening, increased echogenicity of fat, loss of tissue planes, and/or dilated ducts (over 3mm) or lymphatics.[38] A focal heterogeneous hypoechoic mass with thick irregular walls and increased peripheral vascularity, representing an abscess can also frequently be seen (Figure 5a). Aspiration may be nondiagnostic as the abscess contents are thick and contain granulation tissue and cultures are frequently negative for microorganisms. Treatment is percutaneous drainage and antibiotics, although surgical intervention is sometimes needed. MRI can show focal or diffuse skin thickening, thick walled focal mass with variable enhancement and ductal enhancement and lymphadenopathy.[39] Imaging findings are non-specific and a core biopsy should be performed to exclude inflammatory carcinoma if there is no clinical improvement on antibiotics.

Figure 5.

Inflammatory conditions. (A) A 34-year-old woman presented with a palpable painless hard lump in her left breast. Mammogram (not shown) showed an ill-defined asymmetry in the left upper outer quadrant. Corresponding grey scale ultrasound image shows an irregular heterogeneous hypoechoic mass. Ultrasound-guided core biopsy confirmed chronic inflammatory changes and no malignancy. (B) A 54-year-old woman presented with a palpable hard mass and induration of left breast, and left axillary lymphadenopathy. Mammogram (not shown here) showed dense breast tissue and no focal abnormality. Ultrasound showed irregular hypoechoic mass with angular margins and posterior shadowing (arrows). Ultrasound guided core biopsy demonstrated chronic inflammation with necrosis and granuloma formation centered around ducts and lobules. The patient had multiple recurrences and subsequently needed surgical excision. (C) 32-year-old woman with long standing Type I Diabetes presented with a painless firm palpable left breast lump. Mammogram (not shown) showed a vague asymmetry at the site of palpable lump. Ultrasound showed an irregular hypoechoic solid mass with angulated margins (arrows). Biopsy confirmed diabetic mastopathy.

Granulomatous Mastitis

Granulomatous mastitis is a rare condition commonly found in young women and is associated with pregnancy, breast-feeding and oral contraception.[40] Clinically, it often mimics inflammatory cancer and presents as poorly defined areas of thickening and axillary lymphadenopathy. On mammography, it typically presents as an ill-defined focal asymmetry, although it may also present as multiple, small ill-defined masses.[40 41] On ultrasound, it typically presents as an ill-defined hypoechoic mass with increased vascularity in close proximity to ducts (Figure 5b).[40 41] MRI typically shows a low signal mass with ill-defined margins, mimicking malignancy.[41] Diagnosis is made on core biopsy with histology revealing non-caseating, non-infectious granulomas within the breast lobules. Many patients respond to treatment with corticosteroids and are monitored by close clinical and imaging follow up, though some eventually require surgical wide excision.[42] Recurrence is seen in up to 25% of patients.

Diabetic Mastopathy

Diabetic mastopathy (DM) is a rare and benign fibroinflammatory condition of the breast. DM is typically found in premenopausal women suffering from chronic type-I diabetes mellitus, but can also be found in non-diabetic patients with other autoimmune conditions.[43] DM is characterized clinically and radiologically by dense, fibrous breast tissue that is difficult to distinguish from breast cancer. Clinically, it presents as unilateral or bilateral, single or multiple hard, palpable, irregular, painless masses.[43] On mammography it frequently presents as focal asymmetry or mass.[44] On ultrasound it typically shows substantial posterior acoustic shadowing, with irregular and diffuse shadowing zones (Figure 5C).[44,45] The pathogenesis is poorly understood, however current theories suggest that glycosylation due to hyperglycemia may induce extracellular matrix expansion and an autoimmune response, which leads to further matrix proliferation.[43]