Adenoid cystic carcinoma of the breast

Adenoid cystic carcinoma (ACC) of the breast is a rare subtype of breast cancer.

Epidemiology

They account for only 0.1-0.4% of all breast cancers.

Pathology

The tumour demonstrates a strikingly characteristic microscopic pattern similar to that of adenoid cystic carcinoma of the salivary glands. They consist of a mixture of proliferative glandular tissue (an adenoid component) and stromal or basement membrane elements (a pseudoglandular or cylindromatous component). Adenoid cystic carcinoma of the breast displays slowly progressive growth and rarely metastasises to the axillary lymph nodes. On pathologic analysis, it is characterised by the presence of mucin within the pseudocysts found in the tumour.

Radiographic features

Mammography

Typically tends to appear as developing asymmetric densities or irregular masses.

Breast ultrasound

Can appear as irregular, heterogeneous, or hypoechoic masses with minimal vascularity on colour Doppler imaging.

Breast MRI

There is a paucity of data available on the MR imaging features of adenoid cystic carcinoma of the breast. Described features include moderately hyperintense signal on T2-weighted TSE images, a characteristic that may be attributed to the myxoid stroma and cribriform pattern of the tumour ⁷.

Treatment and prognosis

The overall prognosis is comparatively better than the usually unspecified breast cancers. Nodal metastases are rare.

History and etymology

It was first described by F W Foote and F W Stewart in 1946 ⁵.