Mammary Duct Ectasia and Periductal Mastitis

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Mammary duct ectasia is a benign breast disease that can mimic invasive carcinoma clinically. The process that causes the mammary duct ectasia is still being debated but histologically it is characterised by dilation of major ducts in the subareolar region. The breast ducts contain eosinophilic granular secretions and foamy histiocytes. The secretions may undergo calcification and this may be the presenting sign[1] .


Mammary duct ectasia is said to affect primarily perimenopausal parous women but can occasionally occur in children and (rarely) men[2, 3, 4] .

However, a 2021 UK study found mammary duct ectasia to be a common complaint in younger females (mean age 35 years), and those who were overweight/obese, married, had a history of lactation and heavy coffee consumption[5] .


Mammary duct ectasia may present in one of several ways[3] :

  • Microcalcification on a routine mammogram (most common).
  • Nipple discharge - often blood-stained[6, 7] .
  • A palpable subareolar mass.
  • Non-cyclical mastalgia.
  • Nipple inversion or retraction.

Differential diagnosis


Imaging will be required. There are no solid guidelines about which clinical or radiological features accurately distinguish malignancies from lesions with a benign aetiology. Non-invasive methods are preferable. - and breast ultrasound enables the visualisation of the ductal structure and intraductal causes of pathological nipple discharge, and facilitates a subsequent imaging-guided percutaneous biopsy[7] . Higher resolutions and the introduction of Doppler facilitate the differentiation between benign and malignant lesions. Follow-up with regular mammography is recommended.

Other investigations for mammary duct ectasia include[3] :

  • Ductography: this method is occasionally used as an adjunct to mammography in parous women with a unilateral nipple discharge. A small amount of contrast medium is injected into a milk duct and a mammogram performed.
  • Ductal lavage and cytology: cytology of cells obtained by ductal lavage has provided promising results but more research is needed[8] . Doubts have been cast on the diagnostic value of cytology of nipple discharge smears[9] . Only 20% of high-risk women with ductal lavage atypia have atypical hyperplasia or malignancy on subsequent excision[10] .

A mammogram is a useful screening tool, particularly in older women. It is especially sensitive in picking up microcalcification and should be performed whenever complicated, malignant and uncommon forms of mastitis are suspected[11] .


A 2017 Indian study found a more than 40% infective aetiology, so culture (and sensitivities) of discharge is recommended[12] .

Persistent or recurrent cases of mammary duct ectasia are managed with surgical excision of the ducts below the nipple. A focused excision is preferable, as there are lower rates of seroma formation, nipple numbness and nipple inversion[13] .

Image-guided surgery via ductal endoscopy is a promising development[14] .

Periductal mastitis is sometimes used interchangeably with mammary duct ectasia[1] . However, a growing body of evidence suggests that it is a separate entity. Smoking is a risk factor. and a subareolar breast mass (98%) is the most frequent symptom, followed by erythema (41.1%), nipple retraction (36.8%), abscess (36.8%), skin ulceration (25.7%), and mammary duct fistula (19.1%)[15] .

Although the aetiological process is still unknown, bacterial infection is involved and broad-spectrum antibiotics usually promote a rapid improvement[16] . Surgery is occasionally required if there is a residual mass, to confirm the benign nature of the histology and prevent recurrence of infection.

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Further reading and references

  1. Guray M, Sahin AA; Benign breast diseases: classification, diagnosis, and management. Oncologist. 2006 May11(5):435-49.

  2. McHoney M, Munro F, Mackinlay G; Mammary duct ectasia in children: report of a short series and review of the literature. Early Hum Dev. 2011 Aug87(8):527-30. doi: 10.1016/j.earlhumdev.2011.04.005. Epub 2011 May 7.

  3. Hamwi MW, Winters R; Mammary Duct Ectasia

  4. Moon S, Lim HS, Ki SY; Ultrasound Findings of Mammary Duct Ectasia Causing Bloody Nipple Discharge in Infancy and Childhood. J Ultrasound Med. 2019 Oct38(10):2793-2798. doi: 10.1002/jum.14970. Epub 2019 Feb 15.

  5. Mohammed AA; Mammary duct ectasia in adult females risk factors for the disease, a case control study. Ann Med Surg (Lond). 2021 Jan 18

  6. Sajadi-Ernazarova KR, Sugumar K, Adigun R; Breast Nipple Discharge

  7. Yoon JH, Yoon H, Kim EK, et al; Ultrasonographic evaluation of women with pathologic nipple discharge. Ultrasonography. 2017 Oct36(4):310-320. doi: 10.14366/usg.17013. Epub 2017 Apr 9.

  8. West KE, Wojcik EM, Dougherty TA, et al; Correlation of nipple aspiration and ductal lavage cytology with histopathologic findings for patients before scheduled breast biopsy examination. Am J Surg. 2006 Jan191(1):57-60.

  9. Kooistra BW, Wauters C, van de Ven S, et al; The diagnostic value of nipple discharge cytology in 618 consecutive patients. Eur J Surg Oncol. 2009 Jun35(6):573-7. Epub 2008 Nov 4.

  10. Cyr AE, Margenthaler JA, Conway J, et al; Correlation of ductal lavage cytology with ductoscopy-directed duct excision histology in women at high risk for developing breast cancer: a prospective, single-institution trial. Ann Surg Oncol. 2011 Oct18(11):3192-7. Epub 2011 Aug 17.

  11. Kamal RM, Hamed ST, Salem DS; Classification of inflammatory breast disorders and step by step diagnosis. Breast J. 2009 Jul-Aug15(4):367-80. Epub 2009 May 22.

  12. Ramalingam K, Srivastava A, Vuthaluru S, et al; Duct Ectasia and Periductal Mastitis in Indian Women. Indian J Surg. 2015 Dec77(Suppl 3):957-62. doi: 10.1007/s12262-014-1079-5. Epub 2014 May 8.

  13. Zervoudis S, Iatrakis G, Economides P, et al; Nipple discharge screening. Womens Health (Lond Engl). 2010 Jan6(1):135-51.

  14. Lanitis S, Filippakis G, Thomas J, et al; Microdochectomy for single-duct pathologic nipple discharge and normal or benign imaging and cytology. Breast. 2008 Jun17(3):309-13. Epub 2008 Jan 22.

  15. Zhang Y, Zhou Y, Mao F, et al; Clinical characteristics, classification and surgical treatment of periductal mastitis. J Thorac Dis. 2018 Apr10(4):2420-2427. doi: 10.21037/jtd.2018.04.22.

  16. Liu L, Zhou F, Wang P, et al; Periductal Mastitis: An Inflammatory Disease Related to Bacterial Infection and Consequent Immune Responses? Mediators Inflamm. 20172017:5309081. doi: 10.1155/2017/5309081. Epub 2017 Jan 15.