To test the hypothesis that the bleak prognosis of breast cancer in Nigeria may be due, in part, to a subset of patients with rapidly progressing type of breast cancer, a prospective study of 120 breast cancer patients was undertaken. Patients were staged by the UICC-TNM system and the PEV system. Eighty-one (67.5%) of the patients had non PEV while 39 (32.5%) had PEV breast cancer. Of the 24 patients in TNM stage IV, 21 had PEV. Also 17.5% of all breast cancer patient or 53.8% of PEV patients were in the PEV stage with the worst prognosis. Following similar treatment, the median survival of non PEV patients (14 months) was significantly greater than that of PEV patients (6 months). Overall median survival of the cancer patients was 9.5 months. It is concluded that the finding that fully one third of our breast cancer patients have rapidly progressing breast cancer contributes significantly to the poor prognosis of breast cancer in Nigeria.