Popcorn calcification in mammography is seen in the following condition of breast:

Fibroadenomas are very common and are frequently the cause of benign breast biopsy. They occur in very young women (teenagers and women under 30 years of age). They may also become palpable or mammographically visible in older women. Fibroadenoma and carcinoma have overlapping mammographic features and both are common lesions in middle-aged women. With age, fibroadenomas become involuted and heavily calcified. Large lobulated ("popcorn") calcifications have a characteristic mammographic appearance. Ref: Robbins and Cotran pathologic basis of disease edited by Vinay Kumar, Abul K. Abbas, Nelson Fausto, Volume 1, Page 1149.