[A case of prostatic stromal tumor of uncertain malignant potential].

Sarcomas and related proliferative lesions of specialized prostatic stroma are rare. Lesions have been classified into prostatic stromal tumor of uncertain malignant potential (P-STUMP) and prostatic stromal sarcoma based on the degree of stromal cellularity, presence of mitotic figures, necrosis, and stromal overgrowth. STUMPs are considered neoplastic, based on the observations that they may diffusely infiltrate the prostate gland and extend into adjacent tissues, and often recur. Although most cases of STUMPs do not behave in an aggressive fashion, occasional cases have been documented to recur rapidly after resection and a minority have progressed to stromal sarcoma. Here we describe a case of P-STUMP. A 57-year-old male went to his family doctor because of pollakisuria. Digital examination revealed abnormal findings in the prostate, then he was referred to our medical center. The mass was palpable in the left lobe of the prostate; it was elastic hard, surface smooth, about 2 cm in diameter. Serum PSA was elevated slightly (5.42 mg /dl). We diagnosed firstly leiomyosarcoma by transrectal ultra sound guided needle biopsy of the prostate. Then we performed radical prostatectomy. Finally we made the pathological diagnosis of P-STUMP. After 11 months, there is no sign of metastasis or recurrence.