Solitary Fibrous Tumor of the Shoulder Metastasizing to the Small Intestine Presenting as Intussusception: A Case Report

Abstract

Solitary fibrous tumors (SFTs) are rare vascular malignancies that are rarely reported in the upper limb, and even rarer as secondary metastasis to the small bowel. We present a case of a 39-year-old male patient, a known case of metastatic SFT, presenting with severe abdominal pain and vomiting. Computed tomography showed ileo-ileal intussusception. Subsequently, he underwent surgical resection. Histopathological examination showed high-grade sarcoma of the intestinal wall, confirming small intestinal metastasis. This constitutes one of the rare cases of SFTs metastasizing to the small bowel, specifically to the ileum. A review of the literature on similar cases is presented. There appears to be a connection between upper limb SFT and bowel metastasis according to reported literature. However, the scarcity of similar reports makes the generalizability of the conclusion limited.

Keywords: ileo-ileal intussusception; malignancy; rare tumors; rare vascular tumor; solitary fibrous tumor; solitary fibrous tumor (sft).

Figure 1. Axial view of PET/CT done on May 2020. White arrows point to multiple lung nodules representing metastasis.

PET/CT: positron emission tomography/computed tomography.

Figure 2. Axial contrast-enhanced CT image obtained at presentation with abdominal pain, showing evidence of target-like appearance in the subhepatic short segment of the small bowel measuring about 2.7 cm indicating small bowel intussusception.

Figure 3. H&E stain of the malignant solitary fibrous tumor excised from the site of ileo-ileal intussusception. (A) 10x magnification of the excised tumor, which demonstrates the involvement of the intestinal wall with the tumor. There is ulceration from tumor invasion, pointed at by the double arrow. The white arrow points at the normal intestinal lumen. (B) H&E stain 20x magnification shows spindle cells with moderate-to-severe nuclear atypia and brisk mitotic figures.

H&E: hematoxylin and eosin.