A case report of desmoplastic fibroma in a three-year-old black African girl

Background: Desmoplastic fibroma is a very rare bone tumour that is commonly recognised by its striking resemblance to desmoid fibromatosis, commonly seen in soft tissues. Case Presentation: A 3-year-old girl presented to the Oral and Maxillofacial Department with swelling on the lower jaw for 4 months duration. Extra-oral examination revealed: Facial asymmetry due to the discrete swelling on the right mandible measuring 14 x 12cm in widest diameter below the right pre-auricular region to the right mental region. The Craniofacial CT scan showed an expansile jaw mass with destruction of the mandible. There was no evidence of bone formation. Histopathology diagnosis was desmoplastic fibroma of the bone. The tumour cells were weakly positive for MyoD1. Conclusion: Pathologists must know that cells of desmoplastic fibroma may sometimes be weakly positive for MyoD1, as in rhabdomyosarcoma.