Mammary duct ectasia

Mammary duct ectasia is the abnormal widening of one or more breast ducts to greater than 2 mm diameter, or 3 mm at the ampulla. It can be due to benign or malignant processes.

Terminology

Some publications use this term synonymously with periductal mastitis ⁷ or plasma cell mastitis ^10,11, while others suggest that they are distinct entities with a different pathogenesis ^8,9 .

Epidemiology

It is more common in females in an age group of 50-60 years (i.e. postmenopausal). It is very rarely seen in males. It can occasionally be seen in children ¹⁴. 

Clinical presentation

Ductal ectasia is often asymptomatic, especially when benign. However, patients with ductal ectasia may present with nonspecific breast symptoms:

• nipple discharge
• nipple retraction
• pain/tenderness
• palpable mass

Pathology

Benign duct ectasia is characterized by chronic inflammatory and fibrotic changes. Inspissation of debris and secretions within the dilated ducts and later calcification of these ductal contents occurs. There is a known association between ductal ectasia and smoking ¹².

Intraductal malignancy can also cause duct ectasia.

Radiographic features

Mammography

• dilated linear branching densities in subareolar region
• variably present rod-like calcifications pointing towards the nipple

Ultrasound

• distended branching or tubular structures with anechoic contents measuring more than 2 mm diameter

MRI

On T1 and T2 weighted images it appears as dilated increased signal intensity branching ducts converging towards the nipple without an overlying mass. Hyperintense signals are due to thick proteinaceous fluid or blood.

History and etymology

It was first described by Haagensen in the year 1951 ³.

Differential diagnosis

For dilated ducts see: differential diagnosis of dilated ducts on breast imaging.

Practical points

Bilateral, subareolar findings of duct ectasia may confidently be assessed as benign (BI-RADS 1 or 2).

A unilateral (asymmetric) mammographic finding of duct ectasia without demonstrated stability on prior studies warrants further evaluation with ultrasound ¹⁵. Features that on ultrasound should raise suspicion for malignancy include nonsubareolar location, hypoechoic intraluminal contents, ductal wall irregularity or indistinctness, or solid parenchymal mass ^9,15.

A solitary dilated duct, a rare type of asymmetric duct ectasia, is suspicious for malignancy and biopsy should be considered (BI-RADS 4) ¹⁵.