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The diagnosis of soft tissue tumors based on small tissue samples may be difficult. We report on an organ confined prostate sarcoma in an adult primarily diagnosed in a small piece of tissue, which spontaneously passed the urethra during voiding.

A patient with a history of pelvic radiation therapy for seminoma presented with a prostatic tumor, which appeared predominantly of high signal intensity on T2-weighted magnetic resonance images; low-signal-intensity tissue also extended to the pelvic sidewall. At surgical pathology, the tumor was determined to be radiation-induced sarcoma of the prostate, and the extraprostatic tissue was postradiation fibrosis.

A patient with sarcoma of the prostate was treated with radical prostatectomy including wide excision of the ipsilateral neurovascular bundle and hemicystectomy. Six years postoperatively he is free of disease, continent with a bladder capacity of 350 cc, voids to completion, and is potent.

9557 Background: Chemoresistant relapsing prostate sarcoma has no standard treatment and the prognosis is extremely poor. Imatinib mesylate may target on tyrosine kinases of platelet-derived growth factor receptor (PDGFR) which has been shown to be important in tumor growth of certain types of soft tissue sarcoma. Thalidomide, itself a potent immunomodulatory agent has exhibited clinical activity in several malignant neoplasms which have been linked to abnormal angiogenesis and tumor vasculature. Case Report: A 38-year-old man who underwent radical cystoprostatectomy in June 2004 for a stage III high-grade soft tissue sarcoma of spindle and round cell type of prostate staged pT2b(8cm) pN0(0/26) M0, received adjuvant radiotherapy up to 6,660 cGy/37Fx postoperatively. Immunohistochemistry study showed vimentin+, CD34+, CD117−, desmin+, SMActind- and S-100−. Distant relapse in lungs was noted in April 2005. Shortly later massive pleural effusion developed. Three cycles of salvage chemotherapy with MAID were given. Tumor assessment disclosed Progressive Disease status and metastatic tumors were chemoresistant. Imatinib mesylate 400 mg once a day plus thalidomide with increment dose to 200 mg/day was chosen as biologic treatment for his devastating condition after an informed consent was obtained. PDGFR immunohistochemistry staining of the paraffin block and gene sequencing are planned. Results: Marked tumor regression reaching very good partial remission and resolution of pleural effusion without recurrence. Dramatic improvement in terms of performance status and cancer-associated symptoms are obvious. Except for skin changes and mild periorbital edema from imatinib, no other significant adverse reactions were noted. Postulated mechanism of action may suggest PDGFR tyrosine kinase inhibition as well as antiangiogenesis. Conclusions: We documented a case of undifferentiated sarcoma of prostate with pulmonary metastases which were refractory to MAID chemotherapy but subsequently regressed on a combination of double biologic agents, imatinib mesylate plus thalidomide. No significant financial relationships to disclose.

A 19-year-old student who had presented with acute urinary retention was referred to our hospital with biopsy diagnosis of proliferating mesenchymal tumor of the prostate. Magnetic resonance imaging showed enlarged prostatic masses. Suspecting prostate sarcoma, we performed a nerve-sparing radical prostatectomy. Histologic diagnosis of the tumor was prostatic malignant phyllodes tumor. Five months after the operation, bilateral obturator lymph node metastases appeared, which were treated with etoposide, ifosfamide, and cisplatin chemotherapy. After a good response was achieved with four cycles of the chemotherapy, pelvic irradiation was added. Since then, there has been no evidence of recurrence for more than 4 years.

Prostate sarcomas are rare but aggressive neoplasms presenting unique therapeutic challenges. We report a case of prostate sarcoma, and discuss disease control and preservation of quality of life. CASE REPORT A 51-year-old healthy male with normal prostate specific antigen was referred to our institution for evaluation of an asymmetrically enlarged nodular prostate and progressive obstructive voiding symptoms. Transrectal ultrasound revealed a multilocular cystic mass replacing the left side of the prostate (fig. 1, A). Pathological examination of the biopsy cores and subsequent chips from transurethral resection of the prostate for acute urinary retention revealed an indeterminate subtype of prostatic sarcoma. Further diagnostic evaluation included pelvic magnetic resonance imaging which demonstrated a complex multilocular solid mass of the left peripheral prostatic lobe displacing the seminal vesicles but without evidence of local invasion (fig. 1, B). Computerized tomography of the chest, abdomen, pelvis and brain, bone scan and fluorodeoxyglucose whole body tumor scan revealed no evidence of metastatic disease. The patient subsequently elected to undergo radical cystoprostatectomy with unilateral sparing of the neurovascular bundle and continent urinary diversion. Pathological examination of the cystoprostatectomy specimen revealed 5 5.5 cm. high grade prostatic sarcoma with focal chondroid differentiation arising from the left prostatic lobe. All surgical margins were negative. The patient presented with bloody urethral discharge 2 months postoperatively. Urethroscopy and biopsy revealed recurrent sarcoma at the level of the external urethral sphincter. Repeat computerized tomography further demonstrated interval development of multiple bilateral pulmonary nodules. The patient was subsequently started on systemic chemotherapy with dacarbazine, ifosfamide, doxorubicin and mesna. DISCUSSION