Which therapy for unexpected phyllode tumour of the breast?

216 consecutive female patients with histologically confirmed phyllode tumour, the largest series yet reported, were operated on from 1970 to 1989 at our institute and followed-up for a mean period of 118 months. The type of surgery in relation to tumour histotype and natural history were investigated in order to identify the best treatment for this rare breast neoplasm when found unexpectedly at the final histological examination. For the 140 benign tumours, 55 enucleations, 52 enucleoresections, 29 wide resections and 4 mastectomies were performed; the 30 malignant lesions were treated with 3 enucleations, 7 enucleoresections, 9 wide resections and 11 mastectomies; the 46 borderline cases received 11 enucleations, 12 enucleoresections, 18 wide resections and 5 mastectomies. 28 underwent radical surgery following histological diagnosis. There were 27 relapses: 11 (7.9%) in benign, 7 (23.3%) in malignant and 9 (19.6%) in borderline cases. The average disease-free intervals were 32 months for benign, 22 months for malignant and 18 months for borderline phyllode tumours. It is concluded that a wide resection in healthy tissue is indispensable for malignant and borderline phyllode tumours, while where benign phyllode tumour is encountered unexpectedly, even if a limited resection was performed, a wait-and-see policy is justified.