Biphasic malignant tumours of the abdominal cavity.

Carcinosarcomas (CS) are uncommon, highly aggressive, biphasic tumours consisting of both sarcomatous and carcinomatous elements. They appear to originate from a common cell of origin, either via transformation from a single premature precursor or conversion of a mature epithelial cell through an epithelial-mesenchymal transition. CS should be considered a unique cancer subtype with cells typically displaying diffuse mitotic activity and widespread atypical mitoses predisposing to early metastasis and a tendency to local recurrence following resection. This review addresses the pathophysiology of CS and discusses its presentation, natural history and management at a variety of sites within the abdominal cavity and retroperitoneum.