Desmoid tumour is relatively rare and generally non-metastatisizing lesion of mesenchymal origin composed of fibrous tissue and fitting in the group of aggressive fibromatosis; it is a locally aggressive proliferative soft-tissue lesion with controversial nature. This tumour accounts for 0.03% of all tumours and 3% of soft-tissue tumours with annual incidence of two to four cases per million. Although desmoid tumours are more common in persons aged 10-40 years than in others, they do occur in young children and older adults; in children the sex incidence is equal. This is a rare case of extra-abdominal desmoid tumour in a 14-year-old girl affected by spastic tetraparesis. To our knowledge no similar cases are present in literature to date.