Definition:

Infantile myofibromatosis (IM) is a benign fibrous tumour of infancy. The most common mode of presentation is with multiple subcutaneous swellings. Most IM lesions occur in neonates or infants under 24 months of age, with few reports of adult onset. It can occur in three forms: solitary, multicentric or generalised. The solitary form is the commonest and occurs as a single cutaneous nodule. The multicentric form involves the skin, subcutaneous tissues, muscles, and bone. The course is generally benign, with no metastases and regression of the tumor over a period of 12 to 18 months. The generalized form is associated with visceral involvement. This condition has serious prognostic implications as there is a 76% mortality from cardiopulmonary or gastrointestinal complications. While most cases of IM appear to be sporadic, there have been several reports of autosomal dominant inheritance pattern. Mutations in the PDGFRB and NOTCH3 genes were recently identified in patients with IM. Treatment options vary widely. Solitary and even multicentric lesions that are confined to the skin and subcutaneous tissues without visceral involvement frequently regress spontaneously. However, calcification and atrophic scars can remain after lesion regression. Extensive surgery has been reported to be beneficial for multicentric disease, as has chemotherapy.