Metaplastic carcinoma of the breast (MCB) is a rare neoplasm, described in approximately 1% of all breast carcinomas. MCB is associated with poor prognosis and correlated with a high recurrence rate and visceral metastases. MCB is generally hormonal receptor-negative; specific treatments are not well defined. The objective of this study was to describe the clinical and pathological features of MCB.
Materials and methods
We included all the patients with diagnosis of MCB, treated in Instituto Nacional de Cancerología (INCan) of México City during the period from 1995 to 2005; all cases had histopathological confirmation by two pathologist. Clinical information, pathological features of the tumor and survival information were collected; descriptive analysis was done.
From 1995 to 2005 the Instituto Nacional de Cancerologia attended 6,610 breast cancer cases; during this period we found 40 (0.6%) cases of MCB, all of them were female with a mean age of 47.9 years old (24–74). Based on the WHO classification, 20 cases were purely epithelial and 20 were mixed. Of purely epithelial cases, 8 (20%) were squamous, 9 (22.5%) spindle cell and 3 (7.5%) adenosquamous. Mixed cases with chondroid metaplasia, osseous metaplasia and carcinosarcoma, were 15 (37.5%), 3 (7.5%) and 2 (5%) patients, respectively. The right breast were more affected than left (58% vs. 42%). Clinical stages I, II and III were 5%, 35% and 52.5%, respectively; no stage IV were documented. All patients but 2 underwent surgery treatment. Relapse occurred in 10 cases (30.3%); recurrence sites were 2 (20%) local and 8 (80%) distant, frequently the bone. Overall survival was 45.2 months. Table 1 shows clinical and pathological features between purely epithelial and mixed types of MCB.
Table 1. Clinical and pathological features between purely epithelial and mixed epithelial MCB.
The prevalence of MCB in INCan from 1995 to 2005 is <1% (0.6%), with the same distribution between purely epithelial and mixed types. Patients with mixed MCB tended to be younger, with larger tumors, and less survival than the purely epithelial group. Clinical stage, type of surgery, systemic treatment, adjuvant treatment and recurrence where similar between both different histological types.