To our knowledge, this is only the eighth case of a gastric SFT available in the English literature.2–8 SFTs account for less than 2% of all soft-tissue tumors and can develop in the central nervous system, pleura, and extrapleural soft tissue.2,9 Although exceedingly rare, they can arise in the viscera of the gastrointestinal tract as in our patient. Although they can develop at any age, the median age of diagnosis is 50 years, with no correlation between age and anatomic location.3,4,9–11 They are more commonly seen in whites and have a similar sex distribution.4,9,10,12,13 They are usually slow growing, painless masses, but depending on the location, they can cause compressive symptoms. Because of secretion of insulin-like growth factor, they can rarely cause a paraneoplastic syndrome, such as hypoglycemia.11,12 Of the 7 previously reported cases of gastric SFTs, only 3 presented with gastrointestinal hemorrhage in the form of melena.2,6,8 Most are well circumscribed or thinly encapsulated, have a central fibrous component, and vary in color from tan/white to red/brown.1,10,12,14 The median tumor size is 6.5 cm, with a range from 0.8 to 21 cm.10,12 The main histologic features of SFTs consist of a combination of patternless cellular areas separated by bands of hyalinized collagen and thin-walled branching HPC-like vessels.12 Thus, many of these tumors were originally described as HPCs, which are rare vascular tumors originally believed to arise from vascular pericytes of Zimmerman; however, subsequent studies have not confirmed a pericytic origin. Therefore, SFT is the current terminology used to encompass all HPC-like lesions.12 Immunohistochemistry is helpful in the diagnosis because of histologic variability, especially for tumors in uncommon locations as in our patient.5 Immunohistochemistry characteristics include positivity for vimentin, CD34, and STAT-6 and negativity for smooth muscle actin, cytokeratin, desmin, S-100 protein, and c-kit (CD117).4,5
The cornerstone of curative therapy includes en bloc resection.3,4,6,13,14 Given tumor vascularity and concern for hemorrhage during resection, preoperative embolization has been proposed to reduce blood loss and increase the chance for surgical success in the case of large tumors.15 Prognosis is difficult to determine because there is no definitive histopathologic criteria differentiating a benign vs malignant course.5,14 However, studies have shown that high mitotic activity, increased cellularity, infiltrative growth, and central necrosis are associated with a more aggressive course.1,4–6,9,11,14 Although histologic characteristics are not reliable predictors of clinical course, malignant cases often present as poorly circumscribed, infiltrative masses; in contrast, polypoid, pedunculated masses like in our patient are usually benign.5,6 The reported 10-year survival rate of SFTs ranges from 54% to 89%.13 Malignant potential is often determined based on its ability to recur or metastasize, which varies based on the location,1,14 with lesions in the abdomen, pelvis, mediastinum, and retroperitoneum behaving more aggressively.12 Recurrence can occur years after resection, and patients are often monitored for recurrence.
SFTs are mesenchymal tumors that can arise throughout the gastrointestinal tract. By eroding into the lumen, they can cause gastrointestinal hemorrhage as in our patient. Although the definitive diagnosis can only be made on microscopic examination correlated with immunostain profile, if a large brown/tan mass is identified on upper endoscopy performed for upper gastrointestinal hemorrhage, SFTs should be considered. Given the vascular nature of these tumors, embolization may be considered before surgical resection.
Author contributions: J. Kimmel wrote the manuscript and is the article guarantor. A. Dikman and C. Hajdu edited the manuscript.
Financial disclosure: None to report.
Informed consent was obtained for this case report.
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