1. Fig. 1c: Cystoprostatectomy specimen
PROSTATE SARCOMA: PITFALLS IN DIAGNOSIS
George EL Choo1, P Nagappan1, Rohana Zainal1, Shobana Devan2, Zahrah Tawil2 and Rohan Malek1 1 Department of Urology, Hospital Selayang 2 Department of Pathology, Hospital Selayang
A 54-year old man presented to a private medical center with acute urinary retention. He was presumed to have a prostatic abscess and a trans-urethral resection of prostate (TURP) was performed. The histopathology at the private centre was reported as nodular hyperplasia of prostate. The patient presented again two months later with recurrent acute urinary retention. The ultrasound was again suggestive of residual prostatic abscess and a computed tomography (CT) was performed. The CT showed a enhancing multi-loculated cystic prostatic mass with bilateral moderate hydroureteronephrosis and his prostate specific antigen (PSA) was ng/ml. The patient underwent a repeat TURP in our institution. Malignancy was suspected based on the intra- operative finding of solid-cystic prostate tissue and lack of purulent discharge. The repeat histopathology examination showed high grade sarcoma. The patient underwent a short course of neo-adjuvant chemotherapy followed by total pelvic exanteration with ileal conduit and end colostomy.
Fig. 1b
Fig. 1c
Fig. 1a
Fig. 1a and 1b: CT showing a multiloculated cystic prostatic mass extending into the bladder with no clear fat plane with the rectum.
Fig. 1c: Cystoprostatectomy specimen
Fig. 2a
Fig. 2b
Fig. 2d
Fig. 2c
Fig 2a: Large pleomorphic and bizarre tumour cells Fig 2b: Tumour cells are negative for cytokeratin Fig 2c: Tumour cells are diffusely positive for vimentin Fig 2d: Tumour cells are positive for smooth muscle actin
Discussion Prostate sarcoma subtypes include leiomyosarcoma and rhabdomyosarcoma, and account for only per cent of all primary prostatic tumours. Prostate leiomyosarcoma occurs in adults but presents at a younger age and has a more aggressive course compared to other types of prostate cancers. As in the case of our patient, the typical presentation is obstructive lower urinary tract symptoms which rapidly deteriorate. The serum PSA is typically not elevated as the tumour is non-acinar in origin. The radiological characteristics of prostate sarcoma are not uniform and have not been widely reported in literature. Radical excision of the tumour is difficult due to its aggressive nature and almost half of patients who undergo surgery have residual disease. Multi-modality treatment with adjuvant radiotherapy and chemotherapy offers the best chance of long term recurrence-free survival. The use of vincristine, adriamycin and cyclophosphamide based chemotherapy in prostate sarcoma is inferred from its use in treating soft tissue sarcoma in other parts of the body. The prognosis of prostate leiomyosarcoma is poor with median survival of less than 2 years. Local recurrences and distant lung metastases can occur despite negative surgical margins. In conclusion, prostate sarcoma is rare and should be suspected when a younger male patient presents with rapidly worsening lower urinary tract symptoms, a large prostate on digital rectal examination and minimal elevation of PSA. A CT finding of a large pelvic mass with heterogenous enhancement and areas of cystic necrosis will further support the diagnosis.
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