Solitary fibrous tumor of the uterus: Case report

Full text: Case presentation: A 51-year-old patient with a diagnosis of solitary fibrous tumor (TFS) in the uterus since 2015. She underwent total hysterectomy and left salpingectomy in June 2015, with positive microscopic margins (R1 resection). Anatomopathological (AP) indicated adult granulosa cells. Immunohistochemistry (IHC) confirmed TFS. She evolved with local recurrence, having been submitted to excision of peritoneal masses and omentectomy on 11/16/18, with free margins. AP indicated a malignant mesenchymal fusoepithelial neoplasm. She evolved with a new recurrence in retroperitoneal lymph nodes, having been submitted to pelvic and retroperitoneal lymphadenectomy, right adnexectomy, appendectomy, lesion excision in the mesorectum on 10/15/2020, with free margins. The patient evolved with new local recurrence, and underwent resection of a supravesical nodule and infrapubic lesions on 03/13/21, with free margins. She underwent adjuvant radiotherapy (RT) in the pelvis at a dose of 45 Gy in 25 fractions in July 2021, associated with the use of hormone therapy (megestrol). Discussion: TFS are uncommon mesenchymal neoplasms of unknown etiology, with an incidence rate of 2.8 per 100.000 individuals. The occurrence in the female genital tract is extremely rare, with about 30 cases described in the literature. They can be diagnosed at all ages, being more common between 20 and 70 years. They affect both genders equally. They are usually benign, however about 15% of cases recur and present malignant behavior. There are no established protocols to guide the treatment strategy. The recommended treatment for localized disease is complete surgical resection. There are few data and studies evaluating RT and thus it is not recommended after complete tumor resection. In cases of positive margins or recurrent tumors, RT may be considered. Final comments: TFS is a rare neoplasm, especially in the female genital tract. It usually has a benign evolution. However, in a few cases there is recurrence and malignancy. Studies are needed to evaluate the best therapy for these cases, including radiotherapy. (author)