[Recurrences and metastases of cystosarcoma phylloides (phylloid tumor, WHO). On the 150th birthday of a controversial diagnostic concept].

134 Cystosarcoma phyllodes were been observed in the course of 12 years among the diagnostic and consultative (n = 121) material. 133 tumors occurred in the female, one in the male breast. In 21 cases local recurrences and in 4 cases metastases developed. 6 recurrences following local excision were observed more than once: in one case 10 subsequent recurrent tumors, the last of these in the chest wall after mastectomy. Histopathologically, the recurrences were identified as benign (1 case), as borderline tumors (2 cases) and as malignant cystosarcoma (8 cases). In 10 further cases (48% of the recurrences) a stromal sarcoma was predominant. In accordance with the literature, we found in most cases a more aggressive growth and an enhanced malignancy. It is emphasized, that angioinvasive growth in the recurrent tumors can indicate distant metastases. The frequency of the recurrent cystosarcoma in our series was 16%, multiple subsequent tumors occurred in 29% of them. Recurrences are caused by proliferative remnants of the primary tumor following local excision, or they are tumors-de-novo induced by a extratumoral stromal hypercellularity of the surroundings like a new benign cystosarcoma. Therefore an initial wide excision is recommended for the benign and a mastectomy for the malignant cystosarcoma. The site of distant metastases of the 4 cases were the lung and the skeleton (rib and femur). In one case an axillary lymph node was involved by a recurrent giant cell stromal sarcoma. The interval between primary and metastases was 7 months to 5 years, between recurrent tumor and metastases 6 to 24 months or both tumors were observed simultaneously. Following the recent literature, distant metastases occur at an average rate of 19% of the malignant cystosarcomas. In single cases it is impossible to make a sure prognosis of cystosarcoma phyllodes, because recurrences and metastases are observed in all subtypes, but predominantly in the malignant cystosarcomas.