dr james c wittig, orthopedic oncologist, new york, new jersey
About Dr. Wittig
Desmoplastic Fibroma

GENERAL INFORMATION

Desmoplastic fibroma is a benign but aggressive tumor composed of fibroblasts and myoblasts in heavily collagenized stroma. It's a very rare tumor with slow growth  and produces collagen. It characterized also by aggressive intramedullary proliferation of myofibroblasts.   This tumor grows locally in bone in an aggressive manner and destroys the bone. It has significant potential for local recurrence. 

CLINICAL DATA

 Myofibroblasts are well-differentiated within a dense collagen matrix
 Rare, represents 0.1% of all bone tumors
 Microscopically identical to soft tissue fibromatosis
 Fibrous dysplasia may be incorrectly diagnosed as Desmoplastic Fibroma

Differential Diagnosis
 Low grade fibrosarcoma
 Giant cell tumor
 Non-ossifying fibroma
 UBC
 Chondromyxoid fibroma
 Fibrous dysplasia

CLINICAL PRESENTATION

Signs/Symptoms
 Pain and swelling up to 3 years duration
• Associated with pain and deformity in cases of pathologic fracture


Prevalence
 No discernable predilection for any race/sex 

Age
• Range 20 months to 70 years
• Rises mostly in second decade of life (46%)
• 78% cases present before age of 40 years.

Sites
• Craniofacial bones
• Mandible most frequent
• Long bones-----metaphyseal femur, tibia, humerus

RADIOGRAPHIC PRESENTATION

Plain x-ray (Fig. 1-2)
 Well-defined, lucent and expansile
• Possible cortical degradation
• Possible involvement of soft tissue
• More destructive, aggressive growth
• Shown by less-defined borders
• Pathologic fracture may occur
• Described as moth eaten


CT (Fig. 3)
 Useful to demonstrate cortical destruction

MRI (Fig. 4-5)
 Ideal to describe soft tissue involvement
• Sequences often follow that of fibrous tissue with low signal on T1 weighted and T 2 weighted images


Fig. 1: AP and Lat (Fig. 2) Xray of tibia-fibula show a lucent distal tibia lytic lesion. Desmoplastic fibroma of bone often has thickened internal trabeculations and arises within the ceter of medullary canal.


Fig. 2


Fig. 3: Axial CT reconstruction of lower extremity, shows a lytic lesion with posterior cortical destruction during CT guided biopsy.


Fig. 4


Fig. 5

Fig. 4-5: Axial MRI of leg demonstrates a tibia lesion with cortical destruction and soft tissue involvement.


PATHOLOGY

Gross
 Lesion ranges from 3 cm to 10 cm in size
• Grey/white, solid, and fibrous
• Resemble desmoid soft tissue tumors


Microscopic
 Lesion consists of spindle-shaped fibroblasts with dense collagen
• Irregular cellular consistency within lesion
• Low mitotic activity, nucleoli are absent
• Difficult to differentiate from secondary reactive fibrosis 
• Entrapped remnants of bone are often present

PROGNOSIS

Biological Behavior
 Exhibits locally aggressive behavior with infiltrative growth
• No capacity for metastasis


TREATMENT (Fig. 6-12)

• Wide resection recommended
• Possible/low recurrence
• Excision with curettage alone has recurrence rate of 40%
• Addition of cryosurgery to a curettage may lower the recurrence rate
• Role of radiation and chemotherapy are unclear
• Amputation for multiply recurrent tumors or those that are unresectable


Fig. 6


Fig. 7


Fig. 8


Fig. 9


Fig. 10


Fig. 11


Fig. 12

Fig. 6-12: Intraoperative photograph of the lesion (Fig. 6) and steps of the treatment (Fig. 7-12), excision, cryosurgery, gross specimen and cemented internal fixation


Fig. 13: Postoperative image of distal tibia-fibula shows the fixation.

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