Calcifying fibrous pseudotumor in the pelvic cavity: A case report and review of the literature.

Calcifying fibrous pseudotumors (CFPs) are rare benign lesions mostly occurring in the limbs, necks and gastrointestinal tracts of young adults. In the present study, we report the first known case of a pelvic CFP in China in a 67-year-old male patient. The solitary tumor had an extremely regular shape and was in the vicinity of the sigmoid colon. Surgical resection was performed and the tumor was histologically diagnosed as CFP. We reviewed 64 cases of CFPs and discussed the clinical features of this disease in China and other countries. We found that the CFPs were most common in patients aged 18-60 and often had no obvious symptoms. They were immunoreactive for vimentin and factor XIIIa, while negative for CD117 and S100. In China, CFPs were mostly identified in the stomach, possibly associated with Chinese eating. The pathogenesis of this disease remains unclear. More research is needed to confirm the present results.