CASE 10455 Published on 16.03.2013

Desmoplastic fibroma of the mandible

Section

Head & neck imaging

Case Type

Clinical Cases

Authors

Laura Serrano Velasco, Aida Ramos Alcalá, Isabel Pena Fernández, Lourdes Martínez Encarnación and Juan Jose de Haro.

H.G.U. Santa Lucía,
Radiologia; C/Ingeniero Cerón,
nº 12 30840 alhama de Murcia, Spain;
Email:laurasevel@hotmail.com
Patient

15 years, male

Categories
Area of Interest Head and neck ; Imaging Technique Digital radiography, MR, CT, MR-Diffusion/Perfusion, Experimental
Clinical History
A 15-year-old man presented with a painful and palpable mass in the left facial region. He reported a three-month history and limitation of mouth opening. No fever. There was no history of recent trauma. At physical examination the mass was hard.
Imaging Findings
A dental CT revealed a lobulated soft-tissue density mass in the left masticator space. The lesion was lytic and destroyed the left mandibular ramus and left condyle with sun burst periosteal reaction.
On T1-weighted MR images the lesion exhibited an isointense signal to muscle.
The T2-weighted MR image showed a hyperintense and mildly heterogeneous mass involving the left mandibular ramus. The tumour showed an aggressive growth, infiltrating the left mandibular ramus, left medial pterygoid, masseter and temporal muscles and parotid gland. It produced mass effect on the parapharyngeal space.
Contrast-enhanced MR images showed a moderate and homogeneous degree of enhancement.
There was no lymph node enlargement.
Discussion
Desmoplastic fibroma is an extremely rare tumour, with fewer than 200 cases in the published literature. It is a slowly progressing tumour with well-differentiated cells that produce collagen. The mandible is the most common site, involving approximately 40% of the various bony sites, followed by the femur and pelvis. This benign tumour is characterised by aggressive local infiltration. It occurs most often in the first 3 decades, (15.1 years of age on average), and is found equally in men and women. Clinical findings are nonspecific and include pain, soft tissue swelling, joint effusion (if periarticular), and/or pathologic fracture (12%) [1] and [3].
The diagnosis of desmoplastic fibroma is difficult to make radiologically. The posterior mandible is the most frequently involved (e.g., ramus, angle, and molar area). Radiographs may show an osteolytic, expansile, and medullary lesion with well-defined sclerotic margins.
The tumour is often found in the metaphysis, aligned with the long axis of the bone. There is usually a thinned cortex, and the fine intralesional trabeculae give a lobulated appearance that is described as “soap-bubbly.” CT allows more accurate assessment of the extent of bone destruction, including cortical breakthrough and articular invasion. MRI showed the separation of the intraosseous tumour from the bone by displaying the margins clearly. Intramedullary tumour growth and soft-tissue extension are best detected with MRI.
Apart from heterogeneity on MR images, desmoplastic fibroma displays nonspecific low signal intensity on unenhanced T1-weighted images and intermediate to high signal intensity, including areas of low intensity, on T2-weighted images.
The fibroma shows a distinct, inhomogeneous gadolinium enhancement.
Although cross-sectional imaging features of desmoplastic fibroma are nonspecific, some MRI characteristics, such as inhomogeneous contrast enhancement and the presence of low-intensity regions on T2-weighted images, are helpful in determining the diagnosis. The radiologic differential diagnosis includes fibromatosis, rhabdomyosarcoma, neuroblastoma, and lymphoma.
As therapy, surgical resection, radiotherapy, and if necessary also pharmacological treatment is recommended. In respect of the high recurrence rate, surgical resection is the preferred option.
In cases of non-in-sano resected fibromatosis the recurrence rate can be lowered significantly by adjuvant radiotherapy [2] and [3].
Differential Diagnosis List
Desmoplastic fibroma of the mandibule
Fibromatosis
Rhabdomyosarcoma
Neuroblastoma
Lymphoma
Final Diagnosis
Desmoplastic fibroma of the mandibule
Case information
URL: https://www.eurorad.org/case/10455
DOI: 10.1594/EURORAD/CASE.10455
ISSN: 1563-4086