Single-Center Experience with Intimal Sarcoma, an Ultra-Orphan, Commonly Fatal Mesenchymal Malignancy.

BACKGROUND: Intimal sarcoma is a rare malignancy that, clinically and radiographically, often mimics pulmonary embolism. The intravascular tumor tends to disseminate rapidly and metastases can be present at first diagnosis.

METHODS: We reviewed all cases of intimal sarcoma that were diagnosed, treated and followed at the University Hospitals Leuven between April 2006 and April 2016.

RESULTS: We identified 13 patients with a median age of 51 years. In 6 patients initial findings were suggestive of thromboembolic disease. Platelet-derived growth factor receptor α (PDGFRA) amplification was the most prevalent molecular finding, present in 11 patients. The MDM2 gene was amplified in 9 cases, and the EGFR gene in 3 patients. The median overall survival was 13 months. 11 patients underwent surgery. In 5 cases with inoperable and/or metastatic disease chemotherapy was given. Treatment with imatinib was initiated in 4 patients.

CONCLUSIONS: Intimal sarcoma is an extremely rare and aggressive malignancy that has a very poor prognosis. Mimicking thromboembolic disease, diagnosis and treatment can be delayed. Surgery is the mainstay of treatment but is seldom curative. The disease is highly resistant to cytotoxic and targeted treatment. Given the fact that intimal sarcoma commonly expresses more than 1 molecular target, combination therapy might be an option, although toxicity may be a limitation.