Mesenteric fibromatosis is a rare benign mesenteric tumour, characterised by infiltrative growth and high rates of recurrence. Histological examination is the only diagnostic procedure capable of ruling out a malignant mesenteric neoplasm. It is not always possible to perform a radical removal of the tumour mass because it may have infiltrated important anatomical structures. In the present study the Authors report two cases of mesenteric fibromatosis and analyse the main clinical-diagnostic, therapeutic and prognostic problems posed by these tumours.