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Mammary duct ectasia
This is a benign breast disease that can mimic invasive carcinoma clinically. The process that causes the condition is still being debated but histologically it is characterised by dilation of major ducts in the subareolar region. The ducts contain eosinophilic granular secretions and foamy histiocytes. The secretions may undergo calcification and this may be the presenting sign.
Duct ectasia affects primarily middle-aged to elderly parous women but can occasionally occur in children.Smoking is a risk factor. One study found that smokers were three times more likely to develop the condition than non-smokers and the risk appeared to be proportional to the duration of smoking.
The condition may present in one of several ways:
- Microcalcification on a routine mammogram (most common).
- Nipple discharge - often blood-stained.
- A palpable subareolar mass.
- Non-cyclical mastalgia.
- Nipple inversion or retraction.
Imaging will be required. Non-invasive methods are preferable - given the findings are most likely benign. The choice of modality needs to be individualised according to the patient and will depend on a number of factors, including the age of the patient, breast size and whether or not a lump is palpable. Despite advances in investigative techniques, the incidence of false negatives remains high.
A diagnosis can be made by a combination of:
- Ultrasound: this is used as an adjunct to mammography. Higher resolutions and the introduction of Doppler have facilitated the differentiation between benign and malignant lesions.
- 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. Doubts have been cast on the diagnostic value of cytology of nipple discharge smears. Only 20% of high-risk women with ductal lavage atypia have atypical hyperplasia or malignancy on subsequent excision.
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.
Persistent or recurrent cases 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.
Image-guided surgery via ductal endoscopy is a promising development.
This term is sometimes used interchangeably with mammary duct ectasia. However, a growing body of evidence suggests that it is a separate entity. Smoking is a risk factor. It occurs in a younger age group than mammary duct ectasia and presents with pain, a periareolar mass and pus discharge from the nipple. Fistula formation is an occasional complication. Although the aetiological process is still unknown, bacterial infection is involved and broad-spectrum antibiotics usually promote a rapid improvement. Surgery is occasionally required if there is a residual mass, to confirm the benign nature of the histology and prevent recurrence of infection.
Further reading and references
; Mammary duct ectasia: an overview. Breast J. 2011 Nov-Dec17(6):694-5. doi: 10.1111/j.1524-4741.2011.01166.x. Epub
; Benign breast diseases: classification, diagnosis, and management. Oncologist. 2006 May11(5):435-49.
; 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.
; Risk factors for duct ectasia. Breast J. 2005 Jul-Aug11(4):262-5.
; Evaluating nipple discharge. Obstet Gynecol Surv. 2006 Apr61(4):278-83.
; Nipple discharge screening. Womens Health (Lond Engl). 2010 Jan6(1):135-51.
; 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.
; The diagnostic value of nipple discharge cytology in 618 consecutive patients. Eur J Surg Oncol. 2009 Jun35(6):573-7. Epub 2008 Nov 4.
; 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.
; Classification of inflammatory breast disorders and step by step diagnosis. Breast J. 2009 Jul-Aug15(4):367-80. Epub 2009 May 22.
; Microdochectomy for single-duct pathologic nipple discharge and normal or benign imaging and cytology. Breast. 2008 Jun17(3):309-13. Epub 2008 Jan 22.