Malignant solitary fibrous tumor of the seminal vesicle: a case report and review of the literature.

BACKGROUND

Solitary fibrous tumors (SFTs) are rare mesenchymal tumors that can occur in multiple parts of the human body. The majority of SFTs are benign, with malignant cases being exceedingly rare. Although SFTs have been identified in extrapleural sites such as the upper respiratory tract, orbits, and extremities, their occurrence in the seminal vesicles is exceedingly uncommon. To date, only a few cases of seminal vesicle SFTs have been documented, making this case notable for its rarity and clinical presentation.

CASE PRESENTATION

A 43-year-old male patient was incidentally found to have a left seminal vesicle mass on an MRI scan during a routine health check-up. A subsequent PET‒CT scan revealed enlargement of the left seminal vesicle with uneven density and FDG uptake, raising suspicion of malignancy. Although a biopsy suggested a solitary fibrous tumor of the seminal vesicle, the limited tissue sample prevented definitive exclusion of malignancy. This highlights the diagnostic challenges of such rare tumors, particularly when biopsy samples are insufficient. To address this, rapid intraoperative pathology was employed, which confirmed the malignancy and informed the patient of the subsequent surgical approach. The patient underwent laparoscopic excision of the left seminal vesicle tumor, followed by radical excision of both the prostate and seminal vesicles. Postoperatively, the patient recovered well, and final pathology confirmed a malignant solitary fibrous tumor. After five years of follow-up, the patient remained free from recurrence or metastasis.

CONCLUSION

Although the preoperative biopsy in this case established the diagnosis of SFT, it did not definitively ascertain whether it was benign or malignant. Hence, intraoperative frozen section pathology plays a critical role in determining the surgical strategy. This case indicates that satisfactory therapeutic outcomes for seminal vesicle SFTs can be achieved through complete resection via minimally invasive laparoscopic surgery.