When patients present with symptoms related to breast cancer, or when breast masses are found on their own breast examination or clinical breast examination, they need to be differentiated and diagnosed differently from benign and malignant tumors by medical history, physical examination, imaging and histological examination.
An informative medical history can provide clues. The time of finding breast mass, the speed of growth, the change of tumor during menstrual cycle, the presence of inflammatory manifestations on the skin of the surface of the mass, whether regional lymph node enlargement is found, nipple scratching and eczema-like changes, and the color and shape of nipple overflow may all suggest the diagnosis of malignant tumor. Pay attention to asking the patient’s past history, family history, and menstrual fertility for the presence of risk factors for breast cancer, such as history of chest radiation therapy, family history of breast cancer, presence of individual genetic predisposition (brca gene), risk factors confirmed by Gail’s breast cancer risk assessment model (age, age at menarche, age at first childbirth or absence of childbirth, number of previous biopsies for benign breast tumors, previous breast biopsy-confirmed atypical hyperplasia and/or lobular carcinoma in situ, race), etc.
With the gradual implementation of breast cancer screening nationwide and the increase of women’s awareness of breast self-examination, tumors may be diagnosed when they are small in diameter, and the differential diagnosis of benign and malignant tumors at this time mainly refers to the results of imaging and histological examination.
Breast masses
The NCCN recommends the following age groups: under 30 years old, 30 years old and over 30 years old.
1) 30 years and older group
Patients aged 30 years and older with breast masses have a significantly increased risk of breast cancer. Clinical observation alone is not sufficient and bilateral mammography is recommended to be performed first. The lesions are treated separately according to the BI-RADS classification of the lesion.
For BI-RADS category 1, 2 and 3 lesions, breast ultrasound is performed. For lesions in categories 4 and 5, the correlation between clinical examination and imaging was carefully analyzed. If there is no correlation between the masses found on clinical examination and the lesions shown on mammography, continue the examination according to BI-RADS category 1, 2 and 3 lesions. If the clinical examination is consistent with the mammographic findings, a histological diagnosis is obtained by coarse needle aspiration or fine needle localization of the mass for excision.
For BI-RADS category 1, 2, and 3 lesions, if the ultrasound examination is suspicious for malignancy, or if the benignity or malignancy cannot be determined, coarse needle aspiration or fine needle localization of the mass is recommended to obtain a histological diagnosis. If the histological examination is confirmed to be benign and the ultrasound findings are compatible, a clinical examination every 6-12 months and a follow-up of 1-2 years are recommended (follow-up protocol 1), possibly in combination with ultrasound examination. If the mass gradually increases in size during the follow-up period, surgery is recommended; if the mass does not change significantly, routine screening for breast cancer should be performed. If the histological examination is difficult to determine the benignity or malignancy, atypical hyperplasia, benign lesion but microscopic heterogeneity, or LCIS, close follow-up is needed after surgical excision. For patients with atypical hyperplasia and LCIS, medications are recommended to reduce the risk of breast cancer. When malignancy is determined on histological examination, the treatment protocol for breast cancer is followed.
When a single benign lesion is detected by ultrasound, surgical excision, coarse needle aspiration or clinical observation can be performed. It is recommended that only patients with benign lesions less than 2 cm in diameter be followed up according to the follow-up protocol 1, which can be combined with ultrasound or mammography to assess the stability of the tumor. Those with benign lesions determined by surgical excision should be followed up according to the conventional breast cancer screening protocol. For patients with atypical hyperplasia and LCIS, medications are recommended to reduce the risk of breast cancer. When histological examination is determined to be malignant, follow the treatment protocol for breast cancer. If the histological examination by coarse needle aspiration is benign, follow the follow-up protocol 1, which can be combined with ultrasound or mammography to assess the stability of the tumor. During the follow-up period, the mass gradually increases in size and histological examination is performed again. If the lesion is difficult to characterize, atypical hyperplasia, or benign lesions combined with cellular anomalies, excision of the mass is recommended.
Simple cysts suggestive of asymptomatic cysts on ultrasonography can be observed for 2-4 months, and the patient’s symptomatology is the need for clinical management. If the ultrasound suggests a complicated cyst, a puncture followed by a short clinical follow-up (follow-up protocol 1) + mammography (± mammography) is recommended. Histological examination is required if the mass grows progressively during the follow-up period. If bleeding fluid is pierced and the swelling disappears after puncture, 2-4 months of clinical follow-up is required; if the swelling cannot be palpated on breast examination, follow the routine breast cancer screening protocol. If bleeding fluid is pierced, the cyst does not disappear after puncture, or if ultrasound suggests a cystic solid mass (complex cyst), imaging-guided tissue biopsy or surgical excision is recommended. If the histological examination suggests a benign lesion with no obvious cellular anisotropy, follow-up is performed according to follow-up protocol 1, which can be combined with ultrasonography. If the mass gradually increases in size during the follow-up period, a second histologic examination is required; if the mass is stable, breast cancer screening is performed according to the usual protocol. If the histological examination suggests a benign lesion but there is cellular anisotropy, difficult to characterize, atypical hyperplasia, or LCIS, excisional biopsy is recommended. If the histological examination after excisional biopsy suggests benign, breast cancer screening will be performed according to the conventional protocol; if the histological examination suggests atypical hyperplasia or LCIS, in addition to the conventional screening, medication will be taken to reduce the risk of breast cancer; malignant tumors will be treated according to the standard of breast cancer treatment.
If no breast abnormality is detected by ultrasound, histological examination and clinical follow-up can be performed: once every 3-6 months for 1-2 years (Follow-up Plan 2). If the mass gradually increases in size during the follow-up period, histological examination is recommended; if the mass is stable, follow the conventional breast cancer screening method.
2) Under 30 years old group
Breast ultrasound is preferred for patients with breast masses under 30 years of age. The differential diagnosis after ultrasound examination was performed according to the method of the 30 and over 30 years old group. In particular, mammography should be considered only in certain specific cases. patients under 30 years of age are less likely to be malignant, and it is best to follow up a breast mass that is clinically suggestive of benignity for 1-2 menstrual cycles. if the mass disappears after 1-2 menstrual cycles, follow up in the usual way; if the mass persists, ultrasonography should be performed again. Puncture biopsy prior to ultrasound is not recommended.
Nipple overflow without breast swelling
Bilateral nipple discharge with milk-like fluid needs to be ruled out for pregnancy and endocrine disorders. Some medications can also induce bilateral breast overflow, these include: psychotropic drugs, antihypertensives, opioids, oral contraceptives, estrogens, etc. In female patients under 40 years of age with bilateral ductal overflow, clinical follow-up is sufficient, along with advice not to squeeze the breast and to consult immediately if there is a change in the nature of the overflow. in patients over 40 years of age, mammography is performed first and then according to the BI-RADS classification for Treatment.
Persistent spontaneous unilateral nipple-monoductal discharge requires clinical attention. Regardless of the shape of the overflow (clear, plasma, bloody, etc.), guaiac test and cytology are required. Mammography is recommended for all patients and is managed according to the BI-RADS classification. Ultrasonography is also possible. For BI-RADS 1, 2 and 3 lesions, mammography is performed and the procedure is selected based on the findings. For BI-RADS category 4 and 5 lesions, the standard treatment procedures for breast cancer are performed. If the diagnosis is benign or if it is not possible to determine the benignity or malignancy, a mammogram is performed and the resection method is chosen based on the results of the mammogram. If the diagnosis is malignant, follow the standard treatment for breast cancer. If the mammogram result is negative, diagnostic surgery should be considered.
Asymmetric thickening and nodularity
Localized thickening of the breast, nodularity, asymmetry and breast masses are different and it is difficult to define the extent of the lesion during mammography. If the patient is under 30 years of age and has no risk factors for breast cancer, ultrasound examination is performed first. If there is a clinical need to exclude malignancy, mammography may also be performed. Diagnostic mammography is rarely needed at this time due to the difficulty of visualizing breast density and the low risk of breast cancer.
In patients 30 years of age and older, mammography is performed first and may also be combined with breast ultrasound. Thickening, nodularity and asymmetry of the breast are evaluated based on the results of mammography.
If no abnormalities are seen on mammography and ultrasound, clinical evaluation will be repeated at 3-6 months. Annual screening is recommended if lesions are not changing significantly. Histology is recommended if the lesion progresses, or if it appears malignant and the mammogram suggests a BI-RADS category 4-5 lesion.
Skin changes
Abnormal changes in the skin of the breast are a risk sign and require clinical evaluation. Mammography is performed first and can be combined with ultrasonography. Depending on the results of the mammogram, the next step in management is decided. Even if there are no abnormal findings on mammography, further investigations are still needed.
For BI-RADS category 1, 2 and 3 lesions with no significant abnormalities on ultrasound or only suggestive of simple cysts, puncture biopsy or nipple biopsy is required. The decision to use antibiotics is based on the clinical presentation, but further diagnosis of the lesion cannot be stopped during the use of antibiotics. If a biopsy suggests a benign lesion, a repeat history and mammography will be performed, followed by a histological examination and, if necessary, a consultation with a breast specialist and an MRI of the breast, and a BI-RADS 4 or 5 lesion, or an ultrasound examination suggesting a lesion other than a simple cyst, will require a histological examination. In this case, histological examination is obtained by coarse needle aspiration or surgical excisional biopsy. Cysts with thickened cyst walls and cystic solid lesions require excisional biopsy. If the histological examination of the skin suggests malignancy, the treatment will be in accordance with the treatment protocol for breast cancer.
Summary
Clinical judgment of breast lesions is an important part of choosing the best treatment plan. If the physical examination of the breast, imaging and pathology findings are inconsistent with each other, the clinician needs to reassess the patient for possible problems and benefit the patient with further management.