BACKGROUND: Desmoplastic fibroma is an extremely rare primary bone tumor. Its characteristic features include bone destruction accompanied by the formation of soft tissue masses. This condition predominantly affects individuals under the age of 30. Since its histology is similar to desmoid-type fibromatosis, an accurate diagnosis before operation is difficult. Desmoplastic fibroma is resistant to chemotherapy, and the efficacy of radiotherapy is uncertain. Surgical excision is preferred for treatment, but it entails high recurrence. Further, skeletal reconstruction post-surgery is challenging, especially in pediatric cases.
METHODS: Nine years ago, a 14-year-old male patient presented with a 4-year history of progressive pain in his left wrist. Initially diagnosed as fibrous dysplasia by needle biopsy, the patient underwent tumor resection followed by free vascularized fibular proximal epiphyseal transfer for wrist reconstruction. However, a histological examination confirmed a diagnosis of desmoplastic fibroma. The patient achieved bone union and experienced a recurrence in the ipsilateral ulna 5 years later, accompanied by a wrist deformity. He underwent a second tumor resection and wrist arthrodesis in a single stage. The most recent annual follow-up was in September 2023; the patient had no recurrence and was satisfied with the surgery.
CONCLUSIONS: Desmoplastic fibroma is difficult to diagnose and treat, and reconstruction surgery after tumor resection is challenging. Close follow-up by experienced surgeons may be beneficial for prognosis.

OBJECTIVE: Desmoplastic fibroma (DF) is an uncommon intermediate bone tumor rarely involving the skull with unidentified pathogenesis. We report the first case of pediatric temporoparietal cranial desmoplastic fibroma (DF) with a CTNNB1 gene mutation and review the previous literature.
METHODS: A 3-year-old boy had a firm, painless mass on the right temporoparietal region for 22 months. The cranial CT scan showed isolated osteolytic destruction in the outer plate and diploe of the right temporoparietal bone. Gross total resection of the lesion and cranioplasty were performed. After that, a growing epidural hematoma was observed so another operation was performed to remove the artificial titanium plate. Postoperative pathology indicated a DF diagnosis and molecular pathology suggested a missense mutation in exon 3 of the CTNNB1 gene (c.100G > A,p.Gly34Arg).
CONCLUSIONS: Pediatric cranial DF is rare and easy to be misdiagnosed before operation. For cranial DF, lesion resection can be performed and perioperative management should be strengthened. Mutations in the CTNNB1 gene might be one of the molecular pathologic features of DF.

Desmoplastic fibroma (DF) is a rare benign bone tumor adopting an aggressive behavior, representing a challenge for clinical and radiographic diagnosis. This case report focused on a 31-year-old man with a large mandibular lesion with severe displacements of the mandibular teeth. Only a combination of paraclinical findings allows a definitive diagnosis to be made. Cervicofacial MRI revealed a low T1 signal intensity with peripheral enhancement after Gadolinium, and T2 hyperintense signal, while PET scan showed a moderate metabolism. Bone biopsy with immunohistochemical analysis allowed for definitive diagnosis of DF after eliminating the main differential diagnosis (fibrous dysplasia, fibrosarcoma, desmoid tumor, and osteosarcoma). The patient was successfully treated by large mandibular resection and reconstruction with a free-fibular bone flap\".

Desmoplastic fibroma (DF) is a rare, benign, yet locally aggressive bone tumor. It frequently affects the facial bones, and the mandible is the most commonly affected site. Treatment of choice is the removal of the tumor with resection of surrounding bone due to its aggressive behavior. We report a case of DF where the tumor showed resolution and almost complete bone deposition following enucleation. Although DF has a high recurrence rate, the patient remains disease-free 31 months post-surgery.

Desmoplastic fibroma is a benign, rare, but locally aggressive lesion. The intraosseous type rarely presents in the jaws. Desmoplastic fibroma represents the intraosseous counterpart of the soft tissue fibromatoses or desmoid tumor, affects predominantly young people with an affinity for the mandible. The aim of this article is to describe a rare case of spontaneous bone regeneration after resection of intraosseous type of Desmoplastic fibroma. We report a case of intraosseous Desmoplastic fibroma involving right body and ramus of the mandible of a 17 years old, male patient, that underwent surgical procedure by Risdon access to remove all lesion with 1 cm free margins and reconstructed with 2.4 mm plate. After 3 years follow up, spontaneous bone regeneration was found with no signs of recurrence of the lesion. In conclusion, cases of spontaneous bone regeneration after mandibular resection is rare and there are few studies and case report in the literature.

Fibrocartilaginous mesenchymoma (FM) is a rare bone tumor mimicking other fibrocartilaginous lesions on imaging and histologically. Hence, it is difficult to diagnose this entity especially on small biopsies. In this article, we report a case of FM mimicking desmoplastic fibroma on biopsy. A 36-year-old male presented with pain in the left hip. Imaging showed a large expansile lytic lesion involving the acetabulum and pubis. The differential diagnosis was suggestive of giant cell tumor, aneurysmal bone cyst, intraosseous desmoplastic fibroma, and chondrosarcoma. Biopsy revealed a low-grade spindle cell lesion with no evidence of osteoid or chondroid matrix. The lack of cartilaginous nodules in the biopsy prompted a preoperative diagnosis of desmoplastic fibroma. The excised mass showed bland spindle cell proliferation, benign cartilage nodules, and epiphyseal plate-like enchondral ossification suggestive of fibrocartilaginous mesenchymoma. Negative immunostaining for SATB2, CDK4, and MDM2 ruled out low-grade central osteosarcoma. Though GNAS mutations were not performed in this case, rimming of the bony trabeculae at the periphery of the epiphyseal growth plate-like cartilaginous nodule ruled out fibrous dysplasia. The absence of cartilaginous component misleads the diagnosis preoperatively in small biopsies.

Desmoplastic fibromas of bone are extremely rare, slow growing, locally invasive, benign primary bone tumours, bearing close resemblance to the extra-abdominal desmoid tumours of soft tissue. They typically occur in patients around 30 years of age, and most commonly affect the mandible, pelvis and meta-diaphyseal region of long bones. En bloc or wide resection has typically been the treatment of choice to avoid recurrence, however, recent reports support curettage with bone grafting and adjuvant therapy to minimise functional loss. We report a 9-year-old child with a desmoplastic fibroma of right radius. This is an unusual age group for this bone tumor. The tumor was managed with en bloc resection and reconstruction with a non-vascularised fibula autograft. The patient had good functional outcome and no recurrence at 1-year follow-up. Level of Evidence: Level V (Therapeutic).

Desmoplastic fibroma is an extremely rare primary bone tumor that can mimic the presentation of other bone lesions. We describe the case of a middle-aged male with a mass on the left distal femur initially diagnosed as fibrous dysplasia that underwent a wide margin excision followed by a distal femoral replacement to restore anatomy and functionality. Histologic examination of the complete surgical specimen was consistent with a desmoplastic fibroma. This case is the first report of a successful application of endoprosthetic reconstruction after desmoplastic fibroma resection.

The objective of this study is to analyze the clinical and imaging features of desmoplastic fibroma of bone (DFB) for correct diagnosis.
Twenty patients with DFB confirmed by pathology were enrolled, and the imaging presentations were analyzed. Among 20 patients, plain X-ray was performed in all patients, computed tomography (CT) was performed in 12, and magnetic resonance imaging (MRI) was conducted on eight. The clinical and imaging presentations were analyzed and classified to assist in correct diagnosis.
Twenty patients with DFB were retrieved, including eleven males and nine females with an age range of 2-52 years (median 27). The DFB involved the femur in six patients, ilium in five, tibia in four, humerus in two, lumbar vertebra in one, radius in one, and calcaneus in the remaining one. DFB was common in the metaphysis of long bones and could involve the diaphysis and epiphysis. The imaging presentations were divided into four types: the cystic expansile destruction in ten patients, osteolytic destruction in five, mixed destruction in four, and paraosseous destruction in one. CT value was 30 -60 Hu in the lesion area (6 cases CT value45Hu). In eight patients with MRI scanning, the lesion in five patients presented with unevenly equal or low signal on T1WI and unevenly equal or high signal on T2WI, with irregular stripes or patches of low signal on both T1WI and T2WI. In the rest three patients, the lesion was evenly equal or low signal on T1WI and evenly high signal on T2WI. MRI more clearly showed a mass in the adjacent soft tissue and the range of edema in the DFB lesion.
DFB is a rare tumor with strong local aggressiveness, cystic bone destruction, formation of tumor bone trabeculae, soft tissue masses on imaging presentations, low signals on T1WI and T2WI in the lesion, but no periosteal reaction or calcification, which are helpful for diagnosis of the disease and differentiation from other ones.

Giant cell tumor of bone (GCTB) and desmoplastic fibroma (DF) are bone sarcomas with intermediate malignant behavior and unpredictable prognosis. These locally aggressive neoplasms exhibit a predilection for the long bone or mandible of young adults, causing a severe bone resorption. In particular, the tumor stromal cells of these lesions are responsible for the recruiting of multinucleated giant cells which ultimately lead to bone disruption. In this regard, the underlying pathological mechanism of osteoclastogenesis processes in GCTB and DF is still poorly understood. Although current therapeutic strategy involves surgery, radiotherapy and chemotherapy, the benefit of the latter is still debated. Thus, in order to shed light on these poorly investigated diseases, we focused on the molecular biology of GCTB and DF. The expression of bone-vicious-cycle- and neoangiogenesis-related genes was investigated. Moreover, combining patient-derived primary cultures with 2D and 3D culture platforms, we investigated the role of denosumab and levantinib in these diseases. The results showed the upregulation of RANK-L, RANK, OPN, CXCR4, RUNX2 and FLT1 and the downregulation of OPG and CXCL12 genes, underlining their involvement and promising role in these neoplasms. Furthermore, in vitro analyses provided evidence for suggesting the combination of denosumab and lenvatinib as a promising therapeutic strategy in GCTB and DF compared to monoregimen chemotherapy. Furthermore, in vivo zebrafish analyses corroborated the obtained data. Finally, the clinical observation of retrospectively enrolled patients confirmed the usefulness of the reported results. In conclusion, here we report for the first time a molecular and pharmacological investigation of GCTB and DF combining the use of translational and clinical data. Taken together, these results represent a starting point for further analyses aimed at improving GCTB and DF management.