Clinicopathological Characteristics of Mucinous Carcinoma of the Breast in Korea: Comparison with Invasive Ductal Carcinoma-Not Otherwise Specified

Clinicopathological characteristics and prognostic factors of mucinous carcinoma (MC) were compared with invasive ductal carcinoma-not otherwise specified (IDC-NOS). Clinicopathological characteristics and survivals of 104 MC patients were retrospectively reviewed and compared with those of 3,936 IDC-NOS. The median age at diagnosis was 45 yr in MC and 47 yr in IDC-NOS, respectively. The sensitivity of mammography and sonography for pure MC were 76.5% and 94.7%, respectively. MC showed favorable characteristics including less involvement of lymph node, lower stage, more expression of estrogen receptors, less HER-2 overexpression and differentiated grade, and better 10-yr disease-free survival (DFS) and overall survival (OS) (86.1% and 86.3%, respectively) than IDC-NOS (74.7% and 74.9%, respectively). Ten-year DFS of pure and mixed type was 90.2% and 68.8%, respectively. Nodal status and stage were statistically significant factors for survival. MC in Koreans showed similar features to Western populations except for a younger age of onset than in IDC-NOS. Since only pure MC showed better prognosis than IDC-NOS, it is important to differentiate mixed MC from pure MC. Middle-aged Korean women presenting breast symptoms should be examined carefully and evaluated with an appropriate diagnostic work-up because some patients present radiologically benign-like lesions.