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Background and Aim: Leiomyosarcoma (LMS) of the prostate is an uncommon adult prostate tumor that represents less than 0.1 % of prostate malignancies. A highly aggressive clinical course and poor outcome are characteristics of this tumor. Diagnosis at early stage and radical surgery may be curative.
Case report: A 60-year-old man referred with history of obstructive urinary symptoms refractory to medical therapy. The patient underwent simple open transvesical prostatectomy. Pathologic examination revealed primary LMS of prostate. Complementary studies including CT scans of the chest, abdomen and pelvis, as well as a whole-body bone scan were negative for metastasis. Radical prostatectomy and extensive pelvic lymphadenectomy were performed. All tumor margins and lymph nodes were free from tumor and there was no evidence of residual tumor. No evidence of disease recurrence was observed in a follow up period of 3 years.
Conclusion: Acceptable oncological and functional outcomes can be achieved in the management of low grade LMS, by less extensive radical surgery including radical prostatectomy without removal of intra pelvic organs. However, the main recommendation is multimodal therapy including surgery and chemo-radiation therapy.

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Background and Aim: Retroperitoneal liposarcoma (LS) is a rare neoplasm. Well-differentiated LS is a slow-growing subtype with a high rate of recurrence. Despite the high recurrence rate after complete surgical resection, tumor transformation to poorly-differentiated LS is very rare.
Case:  A 45-year-old man with a primary retroperitoneal tumor and the final pathology of well-differentiated LS underwent tumor resection surgery. Local recurrence was detected nine months after surgery. Second surgical resection revealed a poorly-differentiated subtype of LS which was treated with adjuvant radiation therapy. No local recurrence and distant metastasis were detected in a three years follow-up period.
Conclusion: Tumor transformation of well-differentiated retroperitoneal LS to poorly-differentiated subtype is extremely rare. Nevertheless, this rare case was successfully managed in a multi-disciplinary setting using surgical resection and adjuvant radiation therapy.