A young woman with a breast mass: What every internist should know
DIFFERENTIAL DIAGNOSIS
2. Which of the following is in the differential diagnosis of a woman presenting with a breast abnormality?
- Fibrocystic changes
- Breast cyst
- Ductal ectasia
- Simple fibroadenoma
- Intraductal papilloma
- Ductal carcinoma in situ
- Mastitis
- Infiltrating ductal carcinoma
- Phyllodes tumor
All of these choices are part of the differential diagnosis.
Benign breast lesions
Simple fibroadenoma, one of the most common proliferative lesions, is not associated with a higher risk of developing breast cancer.
Fibrocystic changes are the most common nonproliferative lesions. Occasionally breast pain, nipple discharge, or significant lumpiness that varies during the course of the menstrual cycle can occur. The nipple discharge in women with fibrocystic changes is physiologic and pale green to brown in color. It can also be yellow, whitish, clear, or bloody. Bloody nipple discharge is considered pathologic and suggests a process other than fibrocystic changes, necessitating further workup. However, bloody discharge is not always a sign of malignancy, as it can have a benign cause as well.
Ductal ectasia, another nonproliferative lesion, is a result of dilation of subareolar ducts that contain fluid with a crystalline material. It can penetrate the duct, forming a nodule, which causes pain and occasionally fever.
Precancerous and cancerous lesions
Ductal carcinoma in situ is a true neoplasm that has not yet developed the ability to invade through the basement membrane of the ducts. The likelihood of progression to invasive breast cancer depends on the histologic grade, the tumor size, and the patient’s age.
Lobular carcinoma in situ arises from lobules and terminal ducts of breast tissue. Much controversy surrounds this type of tumor, which was thought to be a marker of increased risk of developing ipsilateral and contralateral breast cancer and not to be a malignant lesion itself.15 However, there is emerging evidence to suggest that a pleomorphic variant of lobular carcinoma in situ is associated with development of breast cancer in the same site as the lesion, whereas a nonpleomorphic form is a marker of increased risk of ipsilateral and contralateral breast cancer.16
Invasive ductal and lobular carcinomas are the true invasive breast cancers, with a potential to metastasize.
Phyllodes tumors are uncommon fibroepithelial lesions that account for less than 1% of all breast neoplasms. The median age at presentation is 45 years.17 Despite the historical name “cystosarcoma phyllodes,” these lesions are not true sarcomas and have stromal and epithelial components.
These tumors display very heterogeneous behavior and, based on predefined histologic criteria, are often classified as benign, borderline, or malignant. Benign phyllodes tumors are similar to fibroadenomas in both histology and prognosis, making their diagnosis challenging. The most aggressive phyllodes tumors lose their epithelial component and have high metastatic potential. These tumors often have a biphasic growth pattern, and women may present with a smooth, round, well-defined breast lump that was stable for many years but then started to grow rapidly.17
Surgical resection with wide margins is the primary management of these tumors.18
Mastitis, ie, inflammation of the breast tissue, often presents with symptoms of breast erythema, swelling, tenderness, and nipple discharge. It may be secondary to infection (most often in lactating women) or other causes such as radiation or underlying malignancy. A complication of infectious mastitis is formation of a breast abscess. Underlying malignancy, especially inflammatory breast cancer, is a common cause of noninfectious mastitis and is very important to recognize.19
