Solitary Fibrous Tumor Requiring Abdominal Aortic Vessel Replacement.

Solitary fibrous tumors (SFTs) are mesenchymal tumors, and retroperitoneal occurrence is rare. It has been identified in a variety of soft tissues and organs, such as the pleura, peritoneum, and meninges. In this case, the tumor was in contact with the abdominal aorta, and the invasion was difficult to judge preoperatively. Intraoperatively, it was revealed that the tumor could not be completely removed without aortic replacement. Although SFTs have a generally good prognosis, certain factors, such as tumor incomplete resection, have been reported to increase the risk of recurrence and metastasis. We were able to completely remove the tumor by performing a combined resection of the aorta. The specimens were microscopically disorganized proliferation of spindle-shaped cells. Immunostaining was positive for cluster of differentiation 34 (CD34) and signal transducer and activator of transcription 6 (STAT6). The tumor cells infiltrating into aortic adventitia were observed. This is a valuable case in which artificial blood vessel replacement was able to reduce the risk of recurrence and metastasis due to tumor remnants. We report a rare case of SFT resected with artificial blood vessel replacement.