Abstract 81P
Background
Soft tissue solitary fibrous tumor is still a challenging entity, due to the difficulty in defining the degree of aggressiveness. Few wide series were reported. In the last years different scores were proposed to identify cases at major risk for a poor outcome, according to clinical and histopathological features, but it is still often controversial the definition of the most adequate treatment and follow-up regimen for patients affected by this rare disease.
Methods
A series of 30 soft tissue solitary fibrous tumors treated from 2001 to 2020 was analyzed. Two patients were excluded as early lost at follow-up. 28 patients remained for evaluation. Clinical and radiological follow-up data were collected. Histopathological analysis included evaluation of tumor necrosis, mitotic activity, cellular atypia, Ki-67 index.
Results
20 tumors were located in the lower limb, 6 in the upper limb, 2 in the trunk. All the tumors were subfascial. Dimension was <5 cm in 6 patients, > 5 cm in 22. Disease specific survival was 85,7% at 5 years and 73,5% at 10 years. Four patients were histologically defined as malignant at presentation; three of them died of disease, one is alive with disease (pulmonary). At a follow-up ranging from 24 to 176 months (average 90) only two more patients developed distant metastases. Stratification of the patients according to Demicco and Diebold scores was analogous. None of patients at low risk according to Demicco and Diebold score developed distant failure; one of the patient classified as low risk according to Sugita score died of disease. 58% of the remaining patients presented with or developed distant metastases (50% of Demicco intermediate risk patients and 75% of Demicco high risk score).
Conclusions
Traditional histopathological analysis seems to be able to adequately identify solitary fibrous tumors with a low risk or a high risk for distant failure. Further division of high risk patients in intermediate risk and high risk, as proposed by Demicco, was not validated by our data. Potential new biomolecular markers could maybe further increase the accuracy of actual clinico-histopathological prognostic scores. Further research and multicenter studies are needed.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.