Management of Asymptomatic 6-cm Posterior Mediastinal Solitary Fibrous Tumor
Complete surgical resection with negative margins is the definitive treatment for this patient, as surgery offers the best chance for cure and long-term disease control in solitary fibrous tumors. 1
Primary Treatment Approach
Surgical excision should be performed by a surgeon with specific sarcoma expertise, aiming for complete resection in one specimen bloc with negative margins while preserving uninvolved organs. 1 The 2025 UK guidelines specifically state that retroperitoneal solitary fibrous tumors exhibit a low risk for local recurrence, and the goal should be complete resection with negative margins while preserving uninvolved organs. 1
Key Surgical Principles
The tumor should be resected en bloc with adherent structures, even if not overtly infiltrated, to achieve macroscopically complete resection and minimize microscopically positive margins. 1
Grossly incomplete resection should be avoided as it is of questionable benefit and potentially harmful. 1
The surgical approach will likely require posterolateral thoracotomy given the posterior mediastinal location and 6-cm size, though the specific approach depends on tumor attachment (visceral vs. parietal pleura). 2
Preoperative Considerations
Radiation Sensitivity
The sensitivity of solitary fibrous tumor to radiation therapy should be considered in preoperative planning. 1 While neoadjuvant radiotherapy is not standard, it may be discussed in a multidisciplinary sarcoma tumor board for technically challenging cases. 1
Multidisciplinary Review
All cases should be discussed at a multidisciplinary sarcoma case conference to develop an individualized management plan based on imaging and pathological findings. 1 This is particularly important because the best chance of cure is at the time of primary presentation. 1
What NOT to Do
Conservative management or observation alone is inappropriate for a 6-cm mass, even in an asymptomatic patient. 3, 4 The ACR guidelines rate "conservative management (do nothing)" as 1/9 (usually not appropriate) and "follow-up imaging only" as 1-2/9 for mediastinal masses. 3, 4
Postoperative Management
Adjuvant Therapy
Postoperative radiotherapy following complete resection is of limited value and associated with significant toxicities, and should only be considered in selected cases with a well-defined area at risk for local recurrence. 1 However, adjuvant radiotherapy should be contemplated in high-risk diseases based on final pathology. 5
Risk Stratification
The final pathology should be evaluated for risk factors including mitotic rate, presence of necrosis, and tumor size to determine recurrence risk and guide follow-up intensity. 6 Intermediate or high-risk features may warrant consideration of adjuvant therapy. 5
Follow-Up Strategy
Long-term clinical and radiological follow-up is mandatory for all solitary fibrous tumors, as local recurrences can occur years after seemingly adequate surgical treatment. 2, 6
Follow-up should include clinical evaluation and cross-sectional imaging (MRI preferred for soft tissue characterization). 1, 5
The interval could be shorter initially (3-6 months) and annually after 5 years. 1
Cross-sectional imaging may detect asymptomatic recurrences long before symptoms develop. 1
Common Pitfall
Do not assume benign behavior based on asymptomatic presentation—solitary fibrous tumors have unpredictable clinical course, and even histologically benign-appearing tumors can recur or metastasize. 2, 6 One study reported a recurrence at 124 months follow-up in a patient with initially benign-appearing disease. 2
Prognosis
Complete surgical resection of benign solitary fibrous tumors is usually curative, with excellent long-term outcomes when negative margins are achieved. 2, 7 In one series of 13 patients with complete resection, no recurrence or metastasis occurred during follow-up periods ranging from 2-85 months. 7