Case representation:
After birth a nodular change on the back of the right hand was observed in a male infant. In the following two months, there was a clear progression of the findings, so that at the age of 8 weeks, an MRI was first performed and then a test excision. At this time the lesion already measured 4.7cm x 3.2cm x 4.3cm on the MRI. The histopathological evaluation was difficult, however in the reference pathology, a benign spindle cell lesion without a CTNNB1 mutation or break in the NTRK1-3 genes was diagnosed. After further rapid progression of the tumor occurred, the child was referred to a Department of Pediatric Oncology clinic, where the lesion was deemed non-resectable. After consultation with the CWS (Cooperative Weichteilsarkomstudiengruppe) study center, chemotherapy was advised according to the recommendations for the treatment of fibromatosis. The parents refused chemotherapy.