Histology from the core biopsies of all three breast lesions showed a chronic granulomatous process, most likely sarcoid.

Review of the patient's history and imaging confirmed the patient had a known diagnosis of sarcoidosis (biopsy-proven).

The multifocal abnormality was categorized as M5, U5 (highly suggestive of malignancy), but ultimately was proven to be a benign granulomatous process from sarcoidosis.

Breast manifestations of sarcoidosis are extremely rare, with prevalence reported between <1% and 2% of women with sarcoid, normally presenting between the ages of 30 and 40 ¹.

When symptomatic, patients may present with a firm or hard breast mass and enlarged axillary nodes ¹.

Radiologically, breast sarcoidosis mimics malignancy on both mammograms and ultrasounds, with irregular hypoechoic masses as well as enlarged axillary or intramammary lymph nodes ¹.

When performed, breast MRI has not been shown to help differentiate between sarcoidosis and malignancy. Breast sarcoid lesions can rapidly enhance, wash out, or appear as an irregular mass with gradual enhancement ².

E. Lower et al. reviewed 629 women with sarcoidosis for findings associated with breast disease and found that patients with sarcoid develop breast cancer at the expected frequency ³. In patients with breast disease, they were unable to identify any clinical or radiological findings to distinguish between breast sarcoidosis and malignancy.

In women with sarcoidosis, breast cancer remains a more common finding than breast granulomas. Given the overlapping clinical and radiological features, a biopsy of all suspicious lesions is recommended ³. Histological findings in breast sarcoidosis are those of non-caseating epithelioid granulomas.

Case courtesy of Dr. K. Paisley, University Hospitals Plymouth, UK.