Late Relapse in Genetically Determined Infantile Myofibromatosis. A Case Report and Brief Focus on Recurrences.

Background: Infantile myofibromatosis (IM) is a rare disorder characterized by benign tumors in the skin, subcutaneous tissue, muscle, and occasionally viscera. IM can be hereditary due to PDGFRB or NOTCH3 variants. Treatment is mainly conservative or surgical. Combination regimens have been used in case of disseminated disease.

Observation: We present relapsed disease of IM 11 years after diagnosis in a 2-year-old child initially treated by microscopically complete resection. A new heterozygous c.1687G>A (p.Glu563Lys) mutation in the PDGFRB gene was identified (considered likely pathogenic).

Conclusions: In association with initial treatment, genetic testing is crucial for tailored clinical practice and follow-up in patients diagnosed with IM.