14例恶性潜能未定的前列腺间质肿瘤病例分析

目的: 探讨恶性潜能未定的前列腺间质肿瘤(stromal tumor of uncertain malignant potential,STUMP)的临床及影像学表现、病理特点、治疗及预后情况。方法: 回顾性分析2008年10月至2020年4月北京大学第一医院泌尿外科诊治的14例STUMP患者的临床资料,年龄27~78岁(平均54岁), 病程1~180个月(平均46个月)。以排尿困难、尿路刺激症状为主要表现,直肠指诊可提示前列腺肿物,血清前列腺特异性抗原(prostate specific antigen, PSA)正常或轻度升高,经直肠超声及磁共振提示前列腺肿瘤或前列腺增生结节。结果: 3例仅行前列腺穿刺活检术,2例仅行经尿道前列腺切除术,9例经病理明确诊断后行根治性前列腺切除术或经尿道前列腺切除术。镜下观察前列腺间质细胞过度增生,呈梭形细胞,细胞异型性不明显,核分裂像少见。免疫组织化学检查,PSA均为阴性,波形蛋白均为阳性,CD34及孕激素受体多呈阳性,Ki67阳性指数为1%~20%(平均6%)。病理诊断为恶性潜能未定的前列腺间质肿瘤。随访时间10~96个月(平均65个月), 失访2例,死亡1例,9例术后未见复发,2例因局部复发而多次行经尿道前列腺切除术。结论: STUMP的影像学表现具有特征性,可通过前列腺穿刺活检获得病理学诊断;早期发现确诊,结合临床制定手术为主的综合治疗方案,有助于改善患者预后。

A clinical analysis of 14 cases of prostatic stromal tumor of uncertain malignant potential

Objective: To investigate the clinical and pathologic characteristics, diagnosis, treatment, prognosis and survival of prostatic stromal tumor of uncertain malignant potential. Methods: Overall 14 patients with prostatic stromal tumor of uncertain malignant potential were treated from October 2008 to April 2020, the patient age ranged from 27 to 78 years (mean 54 years). The disease duration was 1 to 180 months (mean duration of 46 months). The clinical manifestations mainly included urinary obstructive symptoms and urethral irritating symptoms. The tumors were located in the peripheral zone or the transition zone. Digital rectum examination indicated prostatic tumor. Serum prostatic specific antigen level was always normal or elevated. Transrectal ultrasonography and magnetic resonance imaging indicated prostatic tumor. Magnetic resonance imaging in showed large, round, well-defined masses, which were diffusely heterogeneous signal on T2 weighted imaging. Following the administration of intravenous contrast medium, the lesion had diffuse and heterogeneous enhancement. Results: In the study, 3 cases underwent prostate biopsy, 2 cases underwent transurethral resection of the prostate, 9 cases underwent radical excision or transurethral resection of the prostate with definite diagnosis of pathologic features. Under the light microscope, the interstitial cells of stromal tumor of uncertain malignant potential were overgrowth and fusiform cells showed some degree of pleomorphism, nuclei with few mitotic figures, and necrosis was not often seen. Immunohistochemical staining showed that prostate specific antigen was negative, while vimentin was positive in the tumor tissue, CD34, progesterone receptor and smooth muscle actin were positive in the majority, and Ki67 positive index was 1%-20% (mean 6%). Twelve cases were followed-up, and the time of survival varied from 10 to 96 months (mean 65 months), two cases were lost to the follow-up, one case died of disease at the end of 10 months, nine cases were free of disease recurrence after surgery, two cases underwent more transurethral resection of the prostate due to local recurrence. Conclusion: STUMP is a very rare tumor of the specialized prostatic stroma with an unpredictable clinical behavior. The clinical manifestations, transrectal ultrasonography and magnetic resonance imaging are valuable for the diagnosis of prostatic stromal tumor of uncertain malignant potential. Its definite diagnosis depends on pathological examination. Up to now, early surgery and combined therapy are effective treatments for prostatic stromal tumor of uncertain malignant potential.