BACKGROUND There are only a limited number of comprehensive reports for retroperitoneal tumors (RPTs). The aim of this study was to perform an interdepartmental data collection for RPTs and to comprehensively clarify the clinical characteristics of this rare disease. METHODS All patients who were diagnosed with RPT from January 2005 to July 2018 in a single institution were included. The analyzed factors included demographics, clinical features, treatment methods, pathological diagnosis, and prognosis. RESULTS A total of 422 patients (215 males and 207 females) with primary RPTs were identified. Biopsy for RPT was performed in 180 patients (43%). Among the 422 patients, 239 (57%) underwent surgery. The most common tissue origin was mesodermal (n = 99, 41%), followed by neurogenic (n = 54, 23%), extragonadal (n = 27, 11%), and metastatic tumors (n = 13, 5%). Among the 99 resected mesodermal tumors, the most common pathological subtypes were liposarcoma (n = 55, 56%) and leiomyosarcoma (n = 16, 16%). The long-term outcomes after surgery were analyzed in patients with intermediate and malignant sarcomas (including liposarcoma, leiomyosarcoma, and others combined, n = 71). The 3- and 5-year disease-free survival rates in the intermediate tumors were 68.2% and 54.2%, respectively, whereas those in the malignant tumors were 48.6% and 28.9%, respectively. The 3- and 5-year overall survival rates in the intermediate tumors were 100% and 94.1%, respectively, whereas those in the malignant tumors were 78.4% and 72.8%, respectively (p = 0.009). CONCLUSIONS The clinical manifestations of RPTs were extremely variable. Recurrence after repeating resection is commonly observed in patients with malignant retroperitoneal sarcoma.

中文翻译：

---

腹膜后肿瘤的临床特征和手术结果：来自多个部门的全面数据收集。

背景技术腹膜后肿瘤（RPT）的综合报道仅有限。这项研究的目的是对RPT进行部门间数据收集，并全面阐明这种罕见疾病的临床特征。方法纳入2005年1月至2018年7月在同一机构诊断为RPT的所有患者。分析的因素包括人口统计学，临床特征，治疗方法，病理诊断和预后。结果共鉴定出422例原发性RPT患者（男性215例，女性207例）。RPT活检在180例患者中进行（43％）。在422名患者中，有239名（57％）接受了手术。最常见的组织起源是中胚层（n = 99，41％），其次是神经源性（n = 54，23％），性腺外（n = 27，11％），和转移性肿瘤（n = 13，5％）。在99例切除的中胚层肿瘤中，最常见的病理亚型是脂肪肉瘤（n = 55，56％）和平滑肌肉瘤（n = 16，16％）。分析了中度和恶性肉瘤（包括脂肪肉瘤，平滑肌肉瘤和其他合并症，n = 71）患者的术后长期预后。中间肿瘤的3年和5年无病生存率分别为68.2％和54.2％，而恶性肿瘤的3年和5年无病生存率分别为48.6％和28.9％。中间肿瘤的3年和5年总生存率分别为100％和94.1％，而恶性肿瘤的3年和5年总生存率分别为78.4％和72.8％（p = 0.009）。结论RPTs的临床表现变化很大。