Purpose: A phyllodes tumor is a rare disease of the breast, which shows various clinicopathological aspects. However, there is some controversy over its clinical behavior, pathologic characteristics, and local recurrence rates. Therefore,
the
clinicopathological characteristics of phyllodes tumor and the risk factor that influence a local recurrence after surgery were analyzed.
Methods: The medical records of 56 patients with a phyllodes tumor who had undergone surgery at the Department of Surgery, Yonsei University, from 1986 to 1998, were analyzed retrospectively. The median follow up period was 57.2 months
(12∼245
months). The microscopic slides were re-examined and the pathologic criteria analyzed were cellular atypia, stromal cellularity, pleomorphism, necrosis, differentiation, tumor margin, and number of mitoses. The malignancy was reclassified using
the
histological criteria reported by Pietruszka et al. (benign was 0∼4 mitoses/10 high- power fields, borderline 5∼9 mitoses, and malignant more than 10 mitoses). The clinical features evaluated included age, preoperative diagnosis, tumor size,
surgical
methods, and local recurrence.
Results: The mean age was 41 years 14∼69 years) and the mean tumor size was 4.5 ㎝ (1∼12 ㎝). Only 9 cases (16.1%) were preoperatively diagnosed as having a phyllodes tumor. The most commonly performed surgical procedures were local or
wide
excision (46 cases, 82.1%), and a mastectomy in 10 cases (17.9%). Out of 56 cases reviewed, 43 (76.8%) were confirmed as being a benign, 7 (12.5%) as being a borderline, and 5 (1.8%) as being a malignant phyllodes tumor. Cellular atypia was minimal
in
40 cases (71.4%) and prominent in 14 cases (25.0%). The stromal cellularity was minimal in 32 cases (57.1%) and prominent in 23 cases (41.1%). Pleomorphism and necrosis were represented in only 1 case (1.8%). The tumor margin was infiltrating in
11
cases (19.6%) and pushing in 43 cases (76.8%). A local recurrence developed in 9 cases (16.1%). There were no dependable histopathological features to predict a local recurrence except for cellular atypia, stromal cellularity, and an infiltrating
tumor
margin.
Conclusion: From the above results, the strong prognostic factors that can be used to predict a local recurrence appear to be cellular atypia, stromal cellularity, and an infiltrating tumor margin.
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