Invasive adenoid cystic carcinoma of the breast

Case contributed by Dr Ralph Nelson

Presentation

Left breast palpable mass for 3 weeks.

Patient Data

Age: 45
Gender: Female

First mammo + spot views

Mammography

The breast tissue demonstrates scattered areas of fibroglandular densities (ACR B).

Irregular spiculated high density mass in the upper inner aspect of the left breast, that persists on spot compression views.

Another focal round smaller asymmetry in the upper outer quadrant.

No abnormal grouped microcalcifications.

BIRADS 5/0: Further assessment with ultrasound with breast biopsy.

Original ultrasound

Ultrasound

Spiculated, not parallel 1.5 x 1.2 cm hypoechoic mass at the left 11:00 radius, with associated mild posterior acoustic shadowing. Associated prominent vascularity seen at its periphery as well as echogenic surrounding halo. Score 4 on strain elastographic images.

Prominent axillary lymph node measuring up to 1.5 cm in maximum diameter with a maximum cortical thickness of 4.7 mm.

Small cyst at 1:00 radius (not shown), corresponding to the focal asymmetry seen on mammo.

 

FNAC + core biopsy

Ultrasound

The mass at 11:00 radius was biopsied using an 18G core biopsy needle. Post biopsy clip inserted.

Using a 22-gauge needle the prominent axillary lymph node was aspirated.

MRI w/ few close up images

MRI

The lest breast mass is heterogeneously dense and there is moderate background of enhancement. Within the upper inner quadrant the spiculated mass measures 1.5 x 1.6 x 1.9 cm.

Follow-up Mammo 7 years later

Mammography

Partial mastectomy with postsurgical changes in the left upper inner quadrant. No signs of recurrence.

Additionally, three (3) axillary sentinel lymph nodes were negative for metastatic disease. 

Case Discussion

Adenoid cystic carcinoma (ACC) of the breast is an extremely rare type of invasive ductal breast cancer, representing between 0.1% to 1% of all breast cancers. It usually clinically manifests as a firm palpable mass. Just like our patient's presentation.

Just as in our case, ACC usually does not spread to lymph nodes or distant sites (nodal disease occurs less than 2% of the time), contributing to its favorable prognosis despite its triple negative status.

Optimal management therapy is controversial. Though our patient did get axillary node dissection; it is reported not being necessary. Neither is chemotherapy. She did however receive adjuvant locoregional radiation therapy. Almost 8 years since her partial mastectomy, no signs of disease recurrence in our patient.

Owing to their rarity, not much is known about the imaging characteristics of breast adenoid cystic carcinoma. 

By presenting the mammographic, sonographic and MRI features of an ACC case, we are hoping to contribute to the Radiopaedia community knowledge of one of the rarest breast cancer subtypes.

Special thanks to Dr. Aldis and the other Breast Center staff radiologists and technologists for their valuable teaching of Breast imaging. 

 

 

 

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