Clinicopathological characteristics, treatment, and survival outcomes of retroperitoneal desmoid-type fibromatosis: A single-institution experience in China.

Retroperitoneal desmoid-type fibromatosis (RPDF) is a rare mesenchymal neoplasm, and it covers a broad spectrum of aggressive monoclonal, fibroblastic proliferation. There is no evidence-based or established optimal treatment available for this intriguing disease yet. Therefore, we here investigated the clinicopathological characteristics, surgical, and survival outcomes in RPDF among Chinese patients. Patients with histologically confirmed RPDF were retrospectively studied from 2010 to 2018 within the West China Hospital of Sichuan University. Demographics, clinicopathological characteristics, treatment, and survival outcome data were collected. Of the 29 cases of RPDF, 19 were females. Tumor diameter ranged from 4 to 40 cm, with a median of 10 cm. Of these patients, surgical resection was the primary treatment adopted for RPDF in 26 cases; while 3 patients underwent watchful waiting. In surgical group, complete and incomplete macroscopic resection was achieved in 21 (80.77%) and 6 (19.23%) cases, respectively. Totally, 21 (80.77%) cases underwent multi-visceral resection. With a median follow-up duration of 48 months, 11 patients experienced tumor progression for the entire cohort. Tumor progression was observed for those patients with incomplete and complete macroscopic resection in 2/5 (40.0%) and 6/21 (28.6%) cases, respectively. In the watchful waiting group, there were no documented cases of RPDF regression. The progression-free survival rate was 86.1%, 71.5%, and 62.3% at 1-, 2-, and 3-years, respectively. RPDFs are rare types of tumor, which have characteristically varied natural histories. Surgical resection had a relative favorable outcome, but some patients were associated with burden of significant surgical complications.