The main method of treating rare mesenchymal tumors PEComas is surgical removal of the tumor and external-beam radiation therapy has historically been considered ineffective. However, the individual cases in the foreign literature as well as this article authors’ experience in the form of the clinical case provided in it shows the possibility of achieving some anti-tumor effect due to the use of aggressive variants of radiation therapy. The use of variations of stereotactic radiotherapy with high dose per fraction and sum dose as an neoadjuvant and definitive treatment looks promising.

Aim. To determine the effectiveness of stereotaxic radiotherapy in patients with liver metastases. Material and Methods. Stereotaxic radiotherapy of liver metastatic tumors was carried out in three fractions for 5–8 days with single focal dose of 10, 12, 15, or 20 Gy. The procedure was performed in 66 patients including 40 (60.5%) women and 26 (39.5%) men. The average age was 60 years (37–82). In 24 (36.5%) cases primary tumor was presented by colorectal cancer, in 12 (18%) – breast cancer, in 7 (10.5%) – ovarian cancer and in 23 (35%) – other malignant tumors. Results. Median follow-up was 14.5 months (range 1.8–53.5). 3 patients did not present data of control examination. Among other 63 patients full effect was established in 16 (25.5%) cases, in 30 (47.5%) patients – partial regression of metastases, in 11 (17.5%) – stabilization, in 6 (9.5%) – progression of tumoral process. Thus, local control rate was 90.5%. Degree III of radiation damage was reported in 2 cases (3%), II – in 7 cases (11%). Conclusion. Stereotaxic radiotherapy seems highly effective and safe method of the treatment of patients with liver metastases and can be recommended for use in patients with limited liver metastases who have been denied in surgery.