Most breast carcinomas exhibit ductal differentiation. However, recognition of less common histologic patterns provides clinically useful data. This report describes a distinctive subtype of breast carcinoma that we have termed "centrally necrotizing carcinoma" (CNC; in this study, N = 34), which is characterized by an unusual and aggressive natural history. Centrally necrotizing carcinomas are composed of well-circumscribed, unicentric nodules with extensive central necrosis that are surrounded by a narrow rim of viable high-grade tumor cells. These tumor cells show minimal ductal differentiation (i.e., tubule formation), but are usually associated with focal ductal carcinoma in situ. The mean age of the patients in this study was 57.5 +/- 11.6 years, and the mean tumor size was 2.5 +/- 1.2 cm. Twenty-eight percent of the patients had positive axillary lymph nodes (mean number of lymph nodes involved, 2.1 +/- 1.2). Ninety-four percent of cases were negative for estrogen and progesterone receptors. In 21 patients (62%), local and/or distant recurrences developed (median time to recurrence, 16.2 months), and, to date, 20 have died from breast cancer (median time to death, 22.5 months). Progression of disease (defined as the development of either a recurrence or death resulting from disease) occurred in 24 patients (71%). Comparison with a set of 26 poorly differentiated ductal carcinomas with (nonextensive, patchy) necrosis matched for age, tumor size, and lymph node status showed a significantly worse progression-free survival rate for the CNC group (p < 0.004). We conclude that CNC is an uncommon but readily identifiable subtype of breast carcinoma and is characterized by early systemic metastasis and an accelerated clinical course.