Pathological outcome of sonographically occult architectural distortions (AD) visible only on digital breast tomosynthesis, and comparison with AD visible also on 2D mammography

To evaluate the rates of malignant and of high-risk lesions among sonographically occult architectural distortions (AD) visible only on digital breast tomosynthesis (DBT) and compare them with AD visible on 2D mammography (2D) and DBT.The records of 1104 DBT-vacuum assisted biopsies (DBT-VAB) were retrospectively reviewed and 218 cases of AD were identified. Complete radiologic examinations and pathologic results were available for 113 sonographically occult AD (1 clinically-detected, 112 clinically-occult). 2D and DBT images were reviewed and AD were divided into a "DBT-detected" group (visible on only DBT) and a "2D-detected" group (visible both in 2D and DBT). The rates of malignant and of high-risk lesions in the "DBT-detected" AD group were calculated and compared to those of the "2D-detected" AD group.Thirty-five (31%) of 113 AD were assessed as "DBT-detected", while 78 (69%) as "2D-detected". DBT-VAB results were benign lesions in 63 (56%) AD, high-risk lesions in 32 (28%) AD and malignant lesions in 18 (16%) AD. Four (12.5%) high-risk lesions were upgraded to malignancy at surgery. Based on final pathology, the malignancy rate was significantly higher in the "DBT-detected" group than the "2D-detected" group (34% [12/35 cases] vs 13% [10/78]; p 0.05). The high-risk lesion rates were 32% (11/35 cases) in the "DBT-detected" group and 22% (17/78 cases) in the "2D-detected" group (p 0.05).AD visible on only DBT proved to be malignant in about one third of cases, which exceeded the malignancy rate of AD visible on also 2D. A similar proportion of DBT-only AD was represented by high-risk lesions.