Solitary fibrous tumors are rare tumors of mesenchymal origin. Although most often observed in the lung pleura, they have been reported in varied extrapleural sites. A 70-year-old male with complicated Crohn’s disease presented with 3 days of nausea, emesis, constipation, and abdominal pain. Computed Tomography (CT) demonstrated mucosal thickening of the middescending colon, consistent with fibrosing stricture. Surgical excision revealed an unusual, 5 cm mass originating in the subserosa. Histopathology of the lesion was notable for a proliferation of cells with spindle and stellate-shaped nuclei and no appreciable mitotic figures, which extended into the muscularis and submucosa. Immunohistochemistry was STAT6 nuclear positive and cytoplasmic CD34 positive, diagnostic for solitary fibrous tumor (SFT). In this case, the SFT infiltrating into the muscularis propria and subserosa caused the stricture and bowel obstruction. This illustrates that while fibrosing strictures are usually the etiology of bowel obstruction in the setting of Crohn’s disease, other rare possible causes should be considered.
Solitary fibrous tumors (SFTs) are rare soft tissue tumors arising from spindle cells of mesenchymal origin [
A 70-year-old male with a long-standing history of complicated Crohn’s disease presented to the Emergency Department (ED) with 3 days of nausea, emesis, abdominal pain, and constipation, consistent with prior bowel obstructions which had resolved with conservative management. Surgical history is significant for bilateral iliac artery angioplasty with transluminal stent placement 3 years prior to presentation. Current medications include loperamide, simethicone, and aspirin. Initial laboratory studies revealed mild anemia and slight hypokalemia but were otherwise unremarkable.
Abdominal CT revealed focal mucosal thickening in the middescending colon, as well as dilation and mild mucosal thickening in proximal segments of the colon (Figure
Abdominal CT scan taken at the L5 level, demonstrating focal mucosal thickening and dilation of the ascending and proximal descending colon.
Gross examination of the excised stricture revealed an unusual mass-like lesion. Histopathological examination of the surgical specimen revealed a fissuring ulcer typical for Crohn’s disease (Figure
H&E demonstrating fissuring ulcer (tumor not in view) at 40 magnification (4x).
H&E demonstrating SFT with focal invasion of the submucosa at 20 magnification (2x).
H&E from stricture site with tumor in view (bottom right) at 40 magnification (4x).
Nuclear STAT-6 positivity at 600 magnification (60x).
CD34 stain marking the cytoplasm of the stellate and spindle cells as well as a staghorn vessel at 200 magnification (20x).
Unfortunately, the patient sustained acute lower limb ischemia due to incidental occlusion of his iliac artery stent, complicated by postoperative multisystem organ failure. He died 11 days after initial presentation.
Solitary fibrous tumors (SFT) are rare soft tissue tumors that arise from spindle cells of mesenchymal origin and are comprised of small cells with spindle-to-stellate-shaped nuclei separated by thin bands of collagen and a mucinous stroma [
On gross examination, SFTs are relatively nondescript, and must be differentiated from other tumors by histopathology and immunohistochemical examination. Differential diagnosis of SFT in the setting of Crohn’s disease includes Inflammatory Fibroid Polyp (IFP), Gastrointestinal Stromal Tumor (GIST), Schwann cell proliferation, adenocarcinoma, and mucosal dysplasia. In particular, IFP has been reported as an occasional complication of inflammatory processes in patients with long-standing Crohn’s Disease [
Reports of SFTs originating in the bowel itself are rare, although a few cases of SFTs originating in the intestinal mesentery have been reported [
In patients with complicated Crohn’s disease, fibrosing strictures are a common pathologic mechanism for bowel obstruction. Chronic and persistent cycles of transmural injury, inflammation, and repair are believed to contribute to increased expression of TGF-
To our knowledge, there are no other cases in the literature of a solitary fibrous tumor causing bowel obstruction directly, rather than by external compression. This case also highlights that even in the setting of Crohn’s disease, processes other than carcinoma or fibrosing stricture formation may contribute to Gastrointestinal Stromal Tumor bowel obstruction.
Solitary fibrous tumors are rare neoplasms arising from the mesenchyme that occur in a wide array of sites. SFTs typically cause clinical symptoms by way of external compression of organs, but this case highlights a novel patient in whom an SFT directly caused stricture and bowel obstruction. Although chronic inflammatory processes are the most common culprits of stricture and bowel obstruction in Crohn’s disease patients, a broad differential diagnosis, including neoplasms such as SFT, is critical in the evaluation of these patients. While we have not observed any similar cases in the literature, this might be related to the rarity of SFTs in this setting, and the fact that such a process would be easily overlooked when the expectation is to find fibrosis.
All data is available for review with Dominion Pathology Associates, Roanoke, Virginia.
This is an original manuscript that has not been previously published and is not being submitted elsewhere.
The authors have no conflict of interest to report.
The authors would like to thank the Open Access Subvention Fund at Virginia Polytechnic and State University for supporting the publication of this case report.