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desmoplastic fibroma

Friday 28 May 2010

Definition: Desmoplastic fibroma is a rare primary tumor of bone that histologically and biologically mimics the extra-abdominal desmoid tumor of soft tissue.

Desmoplastic fibroma usually presents in patients during the first three decades of life and often involves the mandible or long bones of the skeleton.

Its clinical behavior is characterized by a locally aggressive, infiltrating, and destructing course, often with invasion of surrounding tissues but without metastasis.

Although considered a benign lesion, it has a high rate of local recurrences after incomplete surgical excision.

In the maxillofacial location desmoplastic fibroma usually presents as a painless, slow-growing, firm mass, and less commonly reported symptoms include loose teeth, recurrent sinusitis and exophthalmos.

Desmoplastic fibroma is a rare, intraosseous, well-differentiated collagen-producing fibrous tumor characterized clinically by pain.

Epidemiology

Desmoplastic fibroma of bone usually presents during the first three decades of life.

These desmoplastic fibroma-like tumors have been suggested to be part of the tuberous sclerosis complex (TSC).

Localization

- end of a long bone
- pelvis
- mandible.
- maxillofacial region (15619647)

Radiology

In most cases, radiographs reveal a lucent defect that may expand the cortex and, on occasion, has a trabeculated appearance due to irregular thinning of the cortex.

Radiographically, desmoplastic fibromas are expansile, lytic lesions, often with internal trabeculation and “soap bubble” appearance.

Cortical thinning and disruption are common findings, often associated with a soft tissue mass.

In some cases, there may be cortical destruction, suggesting a malignant tumor.

Computed tomography is superior to standard radiography in assessment of the cortical continuity.

Microscopy

Microscopically, the most prominent features are interlacing bundles of dense collagen.

The cells are usually sparse and exhibit no cytologic atypia.

The histologic similarity of desmoplastic fibroma to certain fibrous lesions elsewhere (such as desmoid tumors) suggests that it is an intraosseous counterpart of those lesions.

The tumor has a tendency to recur locally but does not metastasize.

The lack of bone production in this lesion characteristically distinguishes it from fibro-osseous lesions of bone.

Histologically, desmoplastic fibroma consists of a mildly to moderately cellular matrix of fibrocollagenous stromal tissue, lacking cellular pleomorphism, nuclear hyperchromatism, or mitosis.

Both the lack of a capsule and the infiltrative nature of this lesion are hallmarks of desmoplastic fibroma.

Differential diagnosis

- fibrous tumors of bones (fibrous lesions of bones)

- low-grade fibrosarcoma

  • Several histologic findings, including increased number and size of cells, greater nuclear pleomorphism, and increased mitotic activity, suggest a well-differentiated fibrosarcoma.
    - fibrous dysplasia
  • The hallmark of fibrous dysplasia is formation of immature woven bone and a bony matrix that characteristically lacks the osteoblastic rim.

- congenital fibromatosis

  • The solitary congenital fibromatosis (infantile myofibromatosis) is most commonly seen in the craniofacial bones of patients less than 2 years old. It may be distinguished from desmoplastic fibroma by its cellular morphology, nodular growth pattern, and immunohistochemical profile to include positive reactivity for smooth muscle actin and S-100.

- non-ossifying fibroma

  • The fibrogenic stroma on non-ossifying fibroma contains plumper cells in a more cellular storiform pattern, with scattered giant cells and clusters of lipophages and hemosiderin-laden macrophages.

- odontogenic fibroma

  • The odontogenic fibroma is composed of stellate fibroblasts, often arranged in a whorled pattern with fine collagen fibrils and considerable ground substance.
  • Small foci of odontogenic epithelial rests may or may not be present.

Predisposition

- tuberous sclerosis complex

  • TSC-associated desmoplastic fibroma-like tumor

Cytogenetics

- trisomy 8
- trisomy 20

Management

Segmental resection is preferred when a lesion displays signs of aggressive behavior and extension into surrounding soft tissues.

Prognosis

Its clinical behavior is characterized by a locally aggressive, infiltrating, and destructing course, often with invasion of surrounding tissues but without metastasis.

Significant rates of recurrence have been associated with desmoplastic fibroma, depending on the completeness of surgical removal.

Although considered a benign lesion, it has a high rate of local recurrences after incomplete surgical excision.

References

- Desmoplastic fibroma-like tumor of maxillofacial region associated with tuberous sclerosis. Vargas-Gonzalez R, San Martin-Brieke W, Gil-Orduña C, Lara-Hernandez F. Pathol Oncol Res. 2004;10(4):237-9. PMID: 15619647