Intra-abdominal aggressive fibromatosis: a single-center case series of 12 patients focusing on surgical management and clinicopathological features

Intra-abdominal aggressive fibromatosis (AF) is a rare disease with invasive growth and local recurrence. However, few studies have reported the clinical and pathological features of intra-abdominal AF. The aim of this study is to systematically elucidate the clinical characteristics, imaging manifestations, treatment and pathological features of intra-abdominal AF. A total of 12 patients with intra-abdominal AF diagnosed in Xijing Hospital, First Affiliated Hospital of Air Force Medical University from April 2021 to September 2024 were included. All the specimens underwent routine staining and immunohistochemical analysis. The study was approved by the Ethics Review Committee of Xijing hospital. A total of 12 patients with intra-abdominal AF were enrolled (median age: 33 years; range: 16–59 years). Tumors were located in the retroperitoneum (n = 8) or small intestinal mesentery (n = 4), with a mean maximum diameter of 9 cm (6–30 cm). Computed tomography typically showed irregular soft tissue masses with heterogeneous density and enhancement. All patients underwent R0 resection; notably, 10 (83.3%) required combined organ resection due to involvement of adjacent organs or major vessels. Postoperatively, four patients (33.3%) developed mild, transient complications, all of which resolved with conservative management during the same hospitalization. No adjuvant therapy was administered. Immunohistochemistry revealed nuclear β-catenin positivity in all 12 cases (100%), SMA positivity in seven (58.3%), Vimentin positivity in four (33.3%), and a Ki-67 index of 2–20%. CD117 was negative in all cases. At a median follow-up of 23 months (7–48 months), no recurrence or metastasis was observed. Intra-abdominal AF is a rare disease with a high reported local recurrence rate. Early surgery can achieve complete removal in experienced medical centers, and complication rates are acceptable, with good short-term prognosis.