Rare solitary fibrous tumor of the stomach: A case report.

Introduction. Solitary fibrous tumors are rare soft tissue tumors of submesothelial origin and variable malignant potential. The most common localization is pleural, whereas only 0.6% are of extrapleural localization. Solitary fibrous tumor of the peritoneum, especially of gastric serosa is an extremely rare form of this tumor. Case report. We presented a 65- year-old female patient with solitary fibrous tumor of the stomach. Histopathological analysis of removed tissue showed the presence of tumor tissue built of spindle cells, elongated nuclei with moderately abundant cytoplasm. Cells were in a noncohesive arrangement, in smaller areas distributed in the form of palisade. There were amounts of hipocellular connective tissue, hyalinised, with small foci of dystrophic calcification. Mitoses were rare (less than 3/10 HPF). Blood vessels surrounded the connective tissue. Reviewed material did not contain elements of the parent organ. Immunohistochemically there were positivity on CD34 and vimentin, and negativity to S100, SMA, CD117, dezmin, and Ki-67 is < 2%. The change was diagnosed as a solitary fibrous tumor. Conclusion. Considering that benign solitary fibrous tumors of extrathoracic localizations are extremely rare neoplasms with unpredictable biological behavior and the possibility of recurrence, a long-term clinical and endoscopic follow-up on yearly basis of patients with this disease is recommended.