Ductal carcinoma in situ arises from microglandular adenosis and atypical microglandular adenosis in a young woman.

Microglandular adenosis (MGA) and atypical microglandular adenosis (AMGA) are intensely rare and distinctive forms of adenosis of the breast, usually occurring in middle-aged women. Carcinoma arising in MGA is an extremely rare subtype of breast carcinoma, and most reported cases are of invasive carcinoma. Ultrasound and magnetic resonance imaging are accurate imaging modalities for diagnosing these abnormalities. Our goal in this article was to report a rare instance of ductal carcinoma in situ (DCIS) arising from MGA and AMGA in a very young Vietnamese woman who presented with a palpable mass in her right breast for 1 month. During clinical examination and imaging, suspected lesions were found and categorized as BI-RADS 4a. The final histopathological findings confirmed DCIS arising from MGA/AMGA. In this patient, the disease was detected and managed early when the lesion was localized in the duct and there were no signs of invasive ductal carcinoma.