A national cancer database analysis of the clinicopathologic characteristics and outcomes of appendiceal malignant mesenchymal tumors.

The present study aimed to assess the characteristics and outcomes of appendiceal malignant mesenchymal tumors. This was a retrospective case-series study of patients with appendiceal malignant mesenchymal tumors in the national cancer database (2005-2019). The main outcomes were overall survival (OS) and short-term mortality. 53 patients (40 GISTs and 13 sarcomas) were included. 92.6% of GIST patients had stage I disease and 76.9% of GISTs were ≤2 cm. Most appendiceal GISTs were treated with appendectomy or partial colectomy whereas half of patients with appendiceal sarcoma underwent hemicolectomy or subtotal colectomy. Only one short-term mortality was recorded in the sarcoma group. One-third of patients with sarcoma had positive surgical margins versus 5.1% of patients with GISTs. GIST patients had longer median OS (117.1 vs 54.8 months) than sarcoma patients.