Recurrent solitary fibrous tumor in distal lower extremity: An extremely rare entity

Diagnostics and Treatment of Extrameningeal Solitary Fibrous Tumors

Solitary fibrous tumors (SFT) are rare mesenchymal neoplasms that account for less than 2% of all soft tissue masses. In the latest WHO 2020 Classification of Soft Tissue Tumors, extrameningeal SFT was listed as intermediate (rarely metastasizing) or malignant neoplasms. Due to the lack of characteristic clinical features, their diagnosis and treatment remain challenging. The pathogenesis of SFT is often associated with the presence of fusions of the NAB2-STAT6 gene on the 12q13 chromosome. Cytoplasmic CD34 positive staining is considerably characteristic for most SFTs; less frequently, factor XII, vimentin, bcl-2, and CD99 are present. A key factor in the diagnosis is the prevalent nuclear location of STAT6 expression. Radical resection is the mainstay of localized SFTs. In the case of unresectable disease, only radiotherapy or radio-chemotherapy may significantly ensure long-term local control of primary and metastatic lesions. To date, no practical guidelines have been published for the treatment of advanced or metastatic disease. Classical anthracycline-based chemotherapy is applicable. The latest studies suggest that antiangiogenic therapies should be considered after first-line treatment. Other drugs, such as imatinib, figitumumab, axitinib, and eribulin, are also being tested. Definitive radiotherapy appears to be a promising therapeutic modality. Since standards for the treatment of advanced and metastatic diseases are not available, further investigation of novel agents is necessary.

Extrapleural Superficial Solitary Fibrous Tumor on the Posterior Shoulder: A Case Report and Review of the Literature

Objective: Mesenchymal in origin, solitary fibrous tumors are primarily seen within the pleura of the lung or in serosal-lined body cavities. Constituting 1% to 2% of all soft-tissue tumors, solitary fibrous tumors are rare entities, especially when found in extrapleural and in superficial locations. A review of PubMed MEDLINE literature for superficial solitary fibrous tumors revealed 71 reports in case reports and small case series. Methods: In this report, we describe a 74-year-old man with an extrapleural superficial solitary fibrous tumor, as well as present a review of the current published literature to date. Results: We present the clinical course, surgical procedure, histopathological features, and treatment options, as well as present a compilation of the published data on superficial solitary fibrous tumors. Conclusions: Based on the current literature, solitary fibrous tumors are more common in middle-aged women and in the head and neck region. Diagnosis of solitary fibrous tumors requires tissue sampling and staining for immunohistochemical markers. Management of these tumors is based on wide local excision with histologically negative margins. If negative margins cannot be surgically achieved, adjuvant therapies including radiation have been described. With extrapleural manifestations of solitary fibrous tumors seldom reported in the literature, it is our hope that reporting these unusual instances will raise awareness of such disease manifestations and allow for earlier diagnosis and treatment.

A solitary fibrous tumor of the upper limb

Solitary fibrous tumors (SFT) of the upper limb are extremely rare, and we report this tumor in the arm of a 30-year-old male. He is presented with a 22 cm painless mass. Complete surgical excision was performed. The histological diagnosis of SFT was based on the presence of ectatic blood vessels and positive staining for CD34 and vimentin. He remains disease-free at the 3-year follow-up interval. The report aims to increase the awareness of the criteria for the histological diagnosis of SFT, as well as the principles of their surgical excision and follow-up.