[Infantile myofibromatosis. Study of a case using whole body ultrasound and MRI]

Infantile myofibromatosis, despite being considered a rare condition, is the most common fibrous tumour in infancy. It is characterised by the presence of benign fibroblastic-myofibroblastic lesions. It usually occurs in children under two years-old, but it can appear at any age. The solitary form (myofibromas) may affect the skin, subcutaneous cellular tissue, muscle or bone. In the multi-centred form (myofibromatosis), there may also be visceral lesions. The lesions usually regress spontaneously in one or two years, with the prognosis being excellent in these cases. However, when there is visceral involvement, the prognosis is poor and treatment with chemotherapy is indicated. Lung involvement is more associated with a poor prognosis. Although the definitive diagnosis is by histopathology, diagnostic imaging tests are essential for characterising the lesions, establishing the extent of the disease, assessing visceral involvement, and following up the progression of the lesions.