Perivascular epithelioid cell tumor (PEC-ome) of the prostate: ultrasound feature in case report

We describe a rare tumor arising from the prostate gland: Perivascular Epithelioid Cells tumor (PEC-ome). A 54-years old was treated for acute urinary retention with alpha-blockers at presentation due to benign prostate enlargement (65 cc) with asymmetric middle lobe and regular PSA (0.92 ng/ml). After 5 months, patient developed a second acute urinary retention episode and nodules in the left lung; he was treated with transurethral resection of the prostate and left lobectomy.

Histological examination of prostate and lung tissue gave the same diagnosis: leiomyosarcoma with atypical morphological features and patient was observed for 4 months. Considering the uncommon diagnosis, pathological review by the uro-pathologist at our Hospital was done. Additional immunohistochemistry was done and both tumors showed similar and typical features of metastatic PEC-ome (T1b N0 M1). Therefore a new staging showed local and distant progression with prostatic mass and small lung metastasis. Three cycles of Gemcitabine and Pazopanib were administered, but 2 months later a new urinary retention occurred, despite chemotherapy. Patient referred to our Hospital for salvage pelvic surgery with lymph node dissection. Final pathological diagnosis was PEC-ome of the prostate stage pT4 pN0 R0 M1.

PEC-ome is a rare but rapidly invasive mesothelial tumor with early metastatic potential. When this tumors originates from the fibromuscular stroma of the prostate it mimics benign prostatic enlargement and causes LUTS. Expert pathology aided by immunoisthochemistry is the cornerstone of diagnosis. There are no pathognomonic imaging on ultrasound or symptoms suggesting the presence of PEC-ome in early stage. A multidisciplinary approach is necessary and radical surgery should be done to treat this aggressive cancer.