Suspicious mammographic parenchymal abnormalities that are occult at ultrasonography

The study aims to ascertain the significance of ultrasonically occult but mammographically suspicious parenchymal abnormalities, detected at screening mammography.

A retrospective analysis was made on BreastScreen Western Australia data from January 2004 to December 2009. The study group included cases with a mammographic parenchymal abnormality, a negative ultrasound scan and a biopsy under stereotactic guidance. A comparable group of ultrasonically visible carcinomas was used as the control to compare with breast carcinomas in the study sample.

Study population consisted of 469 cases. Twenty per cent (n = 92) of the cases were breast carcinomas, with invasive ductal carcinoma (non-specified) being the most common histological type. There was a statistically significant increase in ductal carcinoma in situ and mucinous carcinoma within this malignant subgroup. Three per cent (n = 17) of the total cohort were borderline lesions on histology. The other 77% (n = 360) of cases were benign histology on core biopsy; however, one was subsequently diagnosed as an interval breast carcinoma.

Stereotactic-guided core biopsy of a suspicious mammographic parenchymal abnormality is warranted, regardless of a normal ultrasound scan, as up to 20% of these cases could be breast carcinomas.