Co-existing malignant lesions in atypical ductal hyperplasia - Pathology, probability, predictors and prognosis

Atypical ductal hyperplasia (ADH) is known to be associated with underlying malignant breast conditions. Previous studies have shown that up to 40% of ADH found in core needle biopsy of the breasts had undiagnosed malignant lesions after excision.

This is a retrospective study on a prospectively maintained database. From 1st January 2005 to 31st December 2014, a total of 262 excision or mastectomy specimens were identified to contain ADH. Clinical, radiological and pathological data were retrieved and analyzed. Correlating factors for the presence of co-existing pre-malignant or malignant conditions were analyzed. Overall survival in patients with or without co-existing malignant breast lesions were evaluated.

95 (36.3%) had co-existing malignant breast lesions within the same specimen. The median age at diagnosis was 49 (Range 17-85). Suspicious breast imaging features (BIRADS 4 or above) and lesions larger than 10 mm on breast imaging were independent risk factor for co-existing malignant pathology (p < 0.001 and 0.005 respectively). After median follow-up interval of 60 months (6-120 months), the overall survival was comparable between the groups of patients having ADH with or without co-existing malignant pathologies (98.2% and 97.9% respectively).

Co-existing malignant lesions were present in up to 36.3% of the pathology specimens containing ADH, in which its presence could be predicted by pre-operative breast imaging.