Breast Masses, Breast Complaints, and Diagnostic Breast Imaging in the Lactating Woman

Publication Date: May 9, 2019
Last Updated: March 14, 2022


Breast Masses

Lactation-specific masses

Accessory breast tissue occurs in 2–6% of women, most commonly in the axilla, with bilaterality in about one-third of cases. Although this tissue is congenital, women may not notice its presence until they experience physiologic breast growth during pregnancy and lactation. (Level IV)
Women may describe fullness during pregnancy and engorgement, and the tissue may be irritating while wearing a bra. If engorgement of this tissue does not resolve after several weeks postpartum, diagnostic imaging is indicated to rule out an alternative diagnosis.
Plugged ducts occur in areas of milk stasis usually localized to a specific quadrant of the breast and resulting from milk that has remained unemptied. Plugs generally are self-limited and resolve with conservative measures such as increasing feeding frequency and gentle massage. (Level IV)
Recurrent or persistent plugging in a ductal distribution that does not resolve with conservative measures is an indication for diagnostic imaging.
Galactocele, also known as a milk retention cyst, results from a persistent plugged duct. Galactocele is the most common benign breast mass in lactating women. (Level IV)
Large galactoceles may require referral to a breast surgeon for serial aspirations for symptomatic control. In addition, galactoceles are at risk for infection due to stasis and may warrant intervention such as drainage. (Level IV)
Phlegmon, a poorly defined fluid collection that results from obstruction and inflammation with or without infection, is well described in the surgical literature on perforated appendicitis and diverticulitis. A similar inflammatory phenomenon occurs in the lactating breast and may present as a tender mass in a ductal distribution, often associated with a recent or concurrent history of mastitis. It may have an irregular, heterogeneous, and vascular appearance on imaging and, therefore, may warrant biopsy to rule out malignancy. (Level IV)
Abscess is a well-defined fluid collection that progresses from unresolved mastitis in ~3% of cases. (Level II)
A galactocele also may undergo conversion to an infected galactocele, and a phlegmon may develop into a drainable fluid collection. Treatment options include antibiotics, aspiration, and catheter drainage. Surgical drainage no longer represents first-line treatment. ()
(IV, I)
Lactating adenomas are painless benign masses that often present in the upper outer quadrant of breast tissue in pregnant and lactating patients, and likely are a result of hormonal stimulation. They can grow large quickly, and involute spontaneously with cessation of lactation. (Level IV)
Biopsy is recommended to establish the diagnosis.
Lactiferous sinuses may be more prominent in breastfeeding women and present as a subareolar mass. (Level IV)

Non-lactation-specific masses

Benign masses that are not specific to lactation include the following:
Fibroadenoma is the most common benign breast mass to present in the reproductive years. ()
Phyllodes tumor, a fibroepithelial lesion similar to a fibroadenoma, has the potential for malignant transformation. Any suspicion of phyllodes requires surgical excision to rule out malignancy. (Level IV)
Cysts are particularly common in women with fibrocystic breasts and are readily classified as simple or complex by ultrasonography. Complex cysts require aspiration for cytologic analysis, whereas simple cysts can be observed. (Level IV)
Pseudoangiomatous stromal hyperplasia is a benign, often irregular, firm mobile mass that can grow large but does not require surgical excision if proven on biopsy. (Level IV)
Intramammary lymph nodes, although uncommon to palpate, are sometimes discovered by patients. Imaging can distinguish between benign versus malignant appearance. (Level I)
Fat necrosis is common after previous breast surgery or trauma; although benign, this condition may present as an irregular palpable mass that may be tender or asymptomatic. (Level IV)
Hematoma can also develop after trauma, such as a motor vehicle accident involving seat belt injury, or vigorous massage in the setting of lactation. In addition to a mass, transient nipple discharge may occur. (Level IV)
Periductal mastitis is an uncommon condition that generally presents in smokers and results from squamous metaplasia of the lactiferous ducts. Patients experience chronic, persistent abscesses, and fistulae in the superficial periareolar region. Optimal treatment is controversial and may include smoking cessation, antibiotic therapy, and/or drainage, with surgical excision reserved for refractory cases. (Level IV)
Idiopathic granulomatous mastitis is an inflammatory disorder of the breast with unclear etiology that results in erythema, abscess, and fistula formation. It most often occurs in young women of Hispanic descent within several years of pregnancy or lactation. (Level IV)
The presentation is variable and can mimic other conditions such as bacterial mastitis or inflammatory breast cancer. Diagnosis is made by exclusion, including negative cultures to rule out infectious mastitis and biopsy to rule out malignancy and to confirm histopathologic evidence of noncaseating granulomas.

Breast cancer

Breast cancer is the most commonly diagnosed malignancy among women in their reproductive years and thus may present during lactation. In addition, breastfeeding women are at risk for postpartum breast cancer, which has higher risk of metastatic spread than other forms of breast cancer. Women with postpartum breast cancer have markedly lower 5-year overall survival when compared with nulliparous cases, even adjusting for biologic subtype and stage at diagnosis. (Level III)
Breast cancer is a broad term that includes preinvasive disease and invasive disease. Diagnosis is established histologically. Management is multidisciplinary in nature and is complex, tailored to the individual patient.

Non-Mass Breast Complaints

Skin conditions

Montgomery glands serve to lubricate the areola and nipple and attract the infant to the breast through olfactory signals. They naturally enlarge during lactation and pregnancy and may not have been noticeable before this time. (Level IV)
They may become obstructed and/or infected like any other sebaceous gland and require treatment with warm compresses and/or topical antibiotics.
Breast edema is common in women with larger breasts. It may become more pronounced during pregnancy and lactation, particularly in the immediate postpartum period associated with engorgement. Reassuring features include bilaterality, edema confined only to the dependent portion of the breast, and improvement with supportive bras. If the patient or provider is concerned, referral can be made for diagnostic imaging and breast surgery evaluation. ()
Nipple bleb an inflammatory lesion of the surface of one or multiple nipple orifices is often white or yellow. Blebs can cause significant latch pain and/or ductal obstruction despite their small size. They may resolve spontaneously. Management for more tenacious blebs includes warm compresses, steroid cream, or procedural unroofing. (Level IV)
If persistent and/or causing plugging and mass-like obstruction, imaging may be warranted in certain patients.
Dermatitis may be localized to the NAC or involves the skin of the breast. The risk of dermatitis may be increased in a breastfeeding patient with a history of atopy and allergy: the mother may have an allergy to ingredients in nipple creams such as lanolin, or allergic to substances the child is touching or ingesting. (Level IV)
Subacute mastitis, or mammary dysbiosis, also may cause nipple flaking, erythema, blebs, and scabbing of the nipple and areola with associated deep breast pain. This condition has been termed ‘‘mammary candidiasis’’ in this past, but newer research is disproving the causative agent as yeast and implicating bacterial imbalance instead. (Level IV)
Paget’s disease is an eczematous oozing itching lesion of the NAC usually associated with underlying breast malignancy. It arises on the nipple and progresses to the areola; this develops in contrast to dermatitis, which generally behaves oppositely. If Paget’s disease is suspected, referral to a breast surgeon for punch biopsy and diagnostic imaging is required. (Level III)
Nipple adenoma, also known as erosive adenomatosis of the nipple, nipple papillomatosis, or papillary adenoma of the nipple, presents with a nipple nodule, nipple erosion, and/or nipple discharge and can mimic Paget’s disease. Nipple adenomas are benign lesions, although they may be associated with preinvasive or invasive lesions. (Level IV)

Nipple discharge

Although breastfeeding women experience physiologic milk expression from their nipple orifices, they also may note other colors of nipple discharge during lactation. Bilateral multiduct discharge that is yellow or green is generally not concerning and considered physiologic. (Level IV)
Serous nipple discharge is more concerning for malignancy and should be evaluated with diagnostic imaging.
Bloody discharge may be due to several conditions including the following:
‘‘Rusty pipe syndrome’’ is the term for transient bilateral multiduct rusty brown or bloody discharge seen in the first few weeks of lactation that resolves spontaneously. (Level IV)
In addition, bloody nipple discharge may occur in up to 24% of women at any point during lactation. (Level IV)
This phenomenon is related to proliferative epithelial changes and increased vascularity in the breast, and is usually self-limited. Persistent bloody nipple discharge presenting after the immediate postpartum period should be evaluated with diagnostic imaging.
Papillary lesions of the breast, which represent a spectrum of disease from benign intraductal papilloma to papillary carcinoma, often present with bloody nipple discharge. Persistent unilateral bloody nipple discharge, particularly from a single duct and/or if associated with a subareolar mass, warrants imaging. (Level IV)
Although pink- or red-tinged expressed milk may raise concern for bloody nipple discharge, this phenomenon may be due to colonization with the pigment-producing bacterium Serratia marcescens and should resolve with antibiotic therapy. (Level IV)

Breast pain

The workup and treatment for breast pain in lactating women with no mass or other physical examination findings to suggest a diagnosis have been previously described and are beyond the scope of this protocol. (Level IV)
Women with pain that does not resolve with appropriate intervention should undergo diagnostic imaging.

Diagnostic Breast Imaging and Breast Biopsy During Lactation

Few international organizations report specific recommendations regarding breast imaging during lactation. The ACR recommends that diagnostic breast imaging in lactating women follow the same guidelines as for nonlactating women, with the exception of ductography that is not recommended in lactation. (Level IV)
We recommend diagnostic breast imaging of almost all breast masses and for several specific non-mass breast complaints.
For diagnostic imaging in a breastfeeding woman, ultrasonography is recommended as the initial imaging modality. If ultrasonography shows suspicious findings or is discordant with clinical examination, additional imaging with mammography or digital breast tomosynthesis (DBT, or ‘‘3D mammography’’) may be indicated. This is related to the fact that mammogram or DBT can visualize architectural distortion and/or calcifications not seen on ultrasonography, as well as delineate extent of disease in the setting of malignancy. (Level IV)
Core needle biopsy rather than fine needle aspiration should be performed after a full diagnostic imaging workup has been completed. Core needle biopsy generally can be performed under ultrasound guidance for a palpable mass. However, if the mass does not have an ultrasound correlate, a woman may be recommended to undergo a stereotactic core needle biopsy with mammographic guidance or a magnetic resonance imaging (MRI)-guided biopsy.
Although there is a small but rare risk of milk fistula, this risk should not preclude biopsy of any suspicious lesion. (Level IV)
Lactating women should also be counseled about a theoretical small increased risk of postprocedural bleeding secondary to hypervascularity. (Level IV)
We do not recommend discontinuation of breastfeeding before biopsy in an effort to minimize these risks. In fact, the inflammation related to abrupt weaning could increase the risk of fistula formation, and lack of alternative drainage routes (e.g., through the nipple) could promote fistula formation through the biopsy tract. (Level IV)
If a woman is diagnosed with a breast malignancy on initial imaging and biopsy, she may be recommended to undergo additional biopsy of suspicious lymph nodes in her regional nodal basins (axillary, internal mammary, and supra- and infraclavicular). Breast radiology and breast surgical oncology also may recommend breast MRI to rule out multifocal or multicentric tumors, contralateral disease, or pectoralis and/or skin involvement. Although MRI is less sensitive in the setting of lactation due to increased parenchymal density and vascularity, it nevertheless is not contraindicated and may provide diagnostic and treatment planning benefit. ()

Recommendation Grading




Breast Masses, Breast Complaints, and Diagnostic Breast Imaging in the Lactating Woman

Authoring Organization

Publication Month/Year

May 9, 2019

Last Updated Month/Year

June 9, 2022

Supplemental Implementation Tools

Document Type


External Publication Status


Country of Publication


Inclusion Criteria

Female, Adult

Health Care Settings

Ambulatory, Emergency care, Hospital, Outpatient, Radiology services

Intended Users

Psychologist, nurse, nurse practitioner, physician, physician assistant


Counseling, Management, Treatment

Diseases/Conditions (MeSH)

D001941 - Breast Diseases, D001943 - Breast Neoplasms, D005693 - Galactosemias, D000038 - Abscess, D007775 - Lactation Disorders, D010144 - Paget's Disease, Mammary, D047688 - Breast Cyst, D003872 - Dermatitis


lactation, Lactation, Breast masses, Breast imaging, lactating adenoma

Source Citation

Katrina B. Mitchell, Helen M. Johnson, Anne Eglash, The Academy of Breastfeeding Medicine, Michal Young, Larry Noble, Sarah Reece-Stremtan, Melissa Bartick, Sarah Calhoun, Sarah Dodd, Megan Elliott-Rudder, Laura Rachel Kair, Susan Lappin, Ilse Larson, Ruth A. Lawrence, Yvonne LeFort, Kathleen A. Marinelli, Nicole Marshall, Catherine Murak, Eliza Myers, Adora Okogbule-Wonodi, Audrey Roberts, Casey Rosen-Carole, Susan Rothenberg, Tricia Schmidt, Tomoko Seo, Natasha Sriraman, Elizabeth K. Stehel, Rose St. Fleur, Lori Winter, Gina Weissman, and Nancy Wight.Breastfeeding Medicine.May 2019.208-214.


Number of Source Documents
Literature Search Start Date
January 1, 1995
Literature Search End Date
May 4, 2019
Description of External Review Process
Yes. The draft protocol is peer reviewed by individuals outside of contributing author/expert panel, including specific review for international applicability. The Protocol Committee's sub-group of international experts recommends appropriate international reviewers. The Chair and/or protocol resource person institutes and facilitates this process. Reviews are submitted to the committee Chair and resource person. The contributing author/expert panel and/or designated members of protocol committee work to amend the protocol as needed. The draft protocol is submitted to the Academy of Breastfeeding Medicine (ABM) Board for review and approval. Comments for revision will be accepted for three weeks following submission. The Chair, resource person and protocol contributor(s) amend the protocol as needed. Following all revisions, the protocol has the final review by original contributor(s) to make final suggestions and ascertain whether to maintain contributing authorship. The final protocol is submitted to the Board of Directors of ABM for approval. A two-thirds majority of Board members' positive vote is required for final approval.
Specialties Involved
Critical Care, Dermatology, Emergency Medicine, Family Medicine, Obstetrics And Gynecology, Oncology, Radiology, Dermatopathology, Medical Oncology, Radiation Oncology, Diagnostic Radiology, Nuclear Radiology, Pathology, Oncology, Oncology, Radiology, Radiology
Description of Systematic Review
Yes. Expert Consensus from systematic reviews with evidence tables.
List of Questions
Breast symptoms require evaluation by physicians and/or lactation consultants and may also require diagnostic breast imaging and/or biopsy. The American College of Radiology (ACR) released new guidelines in 2018 regarding breast imaging of pregnant and lactating women.1 These guidelines state that all breast imaging studies and biopsies are safe for women to undergo while breastfeeding, and also provide recommendations for maximizing examination sensitivity and minimizing biopsy-related complications in this patient population.
Description of Evidence Analysis Methods
ABM refers to the Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence (Levels 1-5). An expert panel is identified and appointed to develop a draft protocol using evidence-based methodology. An annotated bibliography (literature review), including salient gaps in the literature, is submitted by the expert panel to the Protocol Committee.
Description of Evidence Grading
Quality of evidence is based on the Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence2 (levels I–IV) and is noted in parentheses.