Primary Small Intestine Soft Tissue Angiomyofibroma (AFST) with Intussusception: a extremely rare case report and review of literature

Background : Angiofibroma of soft tissue (AFST) is a rare benign mesenchymal tumor, typically occurring in the deep soft tissues of the extremities. Its primary occurrence in abdominal viscera, especially the small intestine, is extremely rare. Histologically, it is characterized by bland spindle cells and an abundant branching vasculature, lacking specific markers and easily confused with other spindle cell tumors. This report presents a case of primary small intestinal AFST manifesting initially as intussusception and intestinal obstruction. Case Presentation : A 43-year-old male patient underwent emergency surgery for acute intestinal obstruction complicated by intussusception. A mass was found within the lumen of the terminal ileum, and segmental small bowel resection was performed. Pathological examination revealed a polypoid mass measuring 6.0×3.0×3.0 cm. Microscopically, the tumor consisted of morphologically uniform spindle cells and numerous thin-walled, branching blood vessels, exhibiting locally infiltrative growth. Immunohistochemistry showed the tumor cells were positive for CD68 and CD163, while negative for CD34, CD117, DOG-1, S-100, β-catenin, among others. A diagnosis of primary small intestinal Angiofibroma of Soft Tissue (AFST) was rendered. Summary : Although benign, AFST can lead to acute abdominal conditions such as intussusception when the tumor reaches a large size, warranting clinical vigilance. Definitive diagnosis relies on characteristic histology, immunophenotype (CD68/CD163 positivity), and molecular genetic testing. Complete surgical excision is the treatment of choice and is associated with a favorable prognosis.