Abstract
A 69-year-old man was referred to our department due to frequent urination, computed tomography (CT) revealed a huge pelvic mass pressuring the bladder and prostate to the right with no signs of direct invasion. No diagnosis was possible with imaging studies alone. En-bloc resection was deemed possible ; therefore, no biopsy was performed preoperatively. Surgery revealed a tumor mainly in the peritoneum and retroperitoneum extending deep into the right inguinal canal. The extracted tumor was 26 cm in diameter and weighed 2030 g. The tumor consisted of a mixture of multi-cystic jelly and solid components. Pathologically, the tumor consisted of spindle cells showing a “patternless pattern”. Immunohistochemical staining showed positive expression for cluster of differentiation (CD) 34, CD99, B-cell lymphoma 2 (Bcl-2), and signal transducer and activator of transcription 6 (STAT6). A final diagnosis of solitary fibrous tumor (SFT) was confirmed.
We report a rare case of SFT that presented with an obscure symptom, i.e., frequent urination.
