Desmoplastic fibroma of the mandible: a series of three cases and review of literature.

The desmoplastic fibroma (DF) is a rare, fibroblastic lesion of bone that histologically resembles the desmoid tumor of soft tissue. Although classified as benign, it frequently demonstrates aggressive behavior, often causing tooth mobility, extensive bone destruction, and has a moderate to high recurrence rate. We present three cases of DF in the mandible: the first in a 13 year old female involving the mandibular body in the region of teeth #s 27-#28, the second in a 57 year old female with a lesion apical to tooth #30, and the third in a 20-year-old female involving the left posterior mandible. Clinical, histologic, immunohistochemical (IHC) and radiographic features of this rare neoplasm are discussed. The challenges encountered in establishing an accurate diagnosis due to significant microscopic overlap with other spindle cell lesions are also detailed. Additionally, the findings of IHC stains including vimentin, smooth muscle actin, S-100 protein, ß-catenin, HHF-35 and proliferation marker, Ki-67 on 3 cases are reported. The potential for misdiagnosis is high, especially in early lesions, since immunohistochemistry has been reported in literature to be inconsistent when differentiating DFs from other spindle cell lesions. A comparative review of DF and similar entities in the jaws with current considerations in treatment and prognosis is presented.

Desmoplastic fibroblastoma (collagenous fibroma): a case identified in the buccal mucosa.

Desmoplastic fibroblastoma is a rare, benign, soft tissue tumor affecting mainly the subcutaneous and muscle tissue. Only five cases identified in the oral cavity have been reported in prior literature. This article presents a case report of a 56-year-old man, with no previous history of trauma, who presented a slow-growing mass in the buccal mucosa. Histopathology and immunohistochemistry staining studies were performed, and a diagnosis of the desmoplastic fibroblastoma was made. The patient has been disease-free for one year.

Collagenous fibroma (desmoplastic fibroblastoma) of the lacrimal gland.

A 53-year-old woman presented with mild right upper eyelid edema without erythema or tenderness. Postcontrast, fat-suppressed, T1-weighted MR images demonstrated a slightly enlarged, mildly enhancing right lacrimal gland, with an internal zone of hypointensity. Histopathologic examination showed scattered spindled to stellate fibroblasts within a myxocollagenous matrix. Cells were immunohistochemically positive for vimentin and negative for smooth muscle actin, desmin, S-100 protein, CD34, cytokeratin, and epithelial membrane antigen. To our knowledge, this is the first report of collagenous fibroma involving the orbit.

Desmoplastic fibroma of the frontal bone.

Desmoplastic fibroma is a benign but locally aggressive tumor arising usually from the mandible, pelvis and long bones with a potential for recurrence. We report a case of desmoplastic fibroma of the frontal bone in a young male.

Desmoplastic fibroma of bone: an immunohistochemical study including beta-catenin expression and mutational analysis for beta-catenin.

Desmoplastic fibroma of bone is a very rare primary bone tumor morphologically resembling desmoid-type fibromatosis, its much more common counterpart of soft tissue. The aim of this study is to investigate the immunohistochemical profile and the involvement of the beta-catenin pathway in desmoplastic fibroma as it is known in desmoid-type fibromatosis. Immunohistochemistry was performed on 13 cases of desmoplastic fibroma for muscle-specific markers, estrogen and progesterone receptors, CD117, beta-catenin, and the potential downstream target of beta-catenin, namely, cyclin D1. In all 13 cases, DNA sequencing was performed for the detection of activating beta-catenin gene mutations. There was no immunoreactivity of CD117, estrogen, and progesterone receptors. Seven cases were immunoreactive for one or more muscle-specific markers. In 6 cases, there was overexpression of beta-catenin in the cytoplasm; in one of these cases, there was also accumulation of beta-catenin in the nucleus. In 6 cases in which DNA sequencing was successful, no beta-catenin mutations were detected. Search in a national database showed that not a single case over a frame of 23 years was associated with occurrence of colon cancer in the same patient. The epidemiological, histological, and immunohistochemical findings in desmoplastic fibroma are suggestive of desmoplastic fibroma being the bony counterpart of the more common desmoid-type fibromatosis of soft tissue. However, the beta-catenin pathway does not seem to have the same essential role in the tumorigenesis of desmoplastic fibroma, as it has in desmoid-type fibromatosis.

[The morphological characteristics of desmoplastic fibroblastoma].

OBJECTIVE: To study the clinical and pathological characteristics of desmoplastic fibroblastoma. METHODS: Three cases of desmoplastic fibroblastoma were evaluated by light microscopy and immunohistochemistry. RESULTS: The patients were all adults, 2 males and 1 female, age range 46 - 62 years (mean 53 years). Clinically, the tumors presented as slowly growing painless masses, which were located in the deep soft tissue of the lower extremity, the subcutaneous tissue of the forearm and the ankle respectively. Grossly, they were well-circumscribed neoplasms with a firm consistency. Histologically, the tumors were composed of paucicellular spindle or stellate-shaped fibroblastic cells embedded in a densely fibrous or fibromyxoid stroma. The neoplastic fibroblastic cells resembled the reactive fibroblasts by containing fine chromatin and small distinct nucleoli without cellular atypia or mitotic figures. Immunohistochemically, the neoplastic cells showed diffuse and strong immunoreactivity for vimentin, focal staining for alpha-SMA, MSA and desmin. CONCLUSION: Desmoplastic fibroblastoma is a benign fibroblastic neoplasm with distinctive clinical and pathological characteristics. It should be differentiated from a variety of reactive or low-grade fibroblastic lesions.

Collagenous fibroma (desmoplastic fibroblastoma) presenting as a parotid mass.

We describe the case of a 50-year-old man who was found to have a painless, slow-growing parotid mass of 10 months duration. At surgery, a well-delimited, lobulated 4x5-cm tumor was located on the deep lobe of the left parotid gland, adhering to the parotid sheath and masseteric fascia. Follow-up 6 years later has shown no evidence of recurrence. Cardinal morphologic features included multiple nodules of sparsely distributed stellate-or spindle-shaped fibroblasts within a collagenous or myxocollagenous stroma. Fascial involvement and entrapment of salivary gland were focally identified at the edges. Tumor cells were diffusely positive for vimentin with faint focal staining for alpha-smooth muscle actin. These findings satisfied the diagnostic criteria for collagenous fibroma (desmoplastic fibroblastoma). Ours represents the first report of this tumor type mimicking a parotid tumor.

Collagenous fibroma (desmoplastic fibroblastoma): a distinctive fibroblastic soft tissue tumor.

Collagenous fibroma is a distinct, benign, fibroblastic/myofibroblastic proliferation, probably neoplasm. It is a slow-growing tumor arising in predominantly subcutaneous tissue. This tumor is composed of stellate-shaped fibroblasts and abundant interstitial collagen. Since none of reported collagenous fibromas recurred, simple excision is an appropriate treatment. Collagenous fibroma should be differentiated from fibromatosis, which has a high risk of local recurrence if simple local excision is done. Fibromatosis is more cellular and shows short fascicular arrangements of tumor cells and greater infiltration at the periphery than collagenous fibroma.

Collagenous fibroma (desmoplastic fibroblastoma): genetic link with fibroma of tendon sheath?

We observed clonal chromosome abnormalities in two fibrous soft tissue tumors diagnosed as collagenous fibroma (desmoplastic fibroblastoma). The involvement of the same band of the long arm of chromosome 11, 11q12, was observed in both tumors. The presence of hitherto unreported similar chromosomal abnormalities in this tumor supports the neoplastic nature of this lesion. In addition, a possible relationship with fibroma of tendon sheath, which also shows rearrangement of 11q12, is suggested. 11q12 might be a common genetic denominator of benign fibroblastic lesions, such as collagenous fibroma and fibroma of tendon sheath.

Desmoplastic fibroblastoma.

Previous reports of a distinctive, fibrous, soft-tissue tumor include eight patients with subcutaneous lesions and six patients with intramuscular lesions. We report a 48-year-old woman with a 2-cm cutaneous and subcutaneous nodule on the left arm with the same histologic features. An excisional biopsy showed a large, well circumscribed tumor replacing the reticular dermis and subcutaneous tissue. The tumor was relatively hypocellular and composed primarily of large, spindled, plump or stellate fibroblasts haphazardly dissecting between thickened fibrotic collagen bundles. The stroma contained a large amount of mucin which was positive with alcian blue at pH 2.5, and relatively numerous mast cells were present. The fibroblastic-like cells were positive with Vimentin and Factor XIIIA and negative with S-100, desmin, actin and keratin.

Collagenous fibroma (desmoplastic fibroblastoma): a clinicopathologic analysis of 63 cases of a distinctive soft tissue lesion with stellate-shaped fibroblasts.

Sixty-three cases of collagenous fibroma (desmoplastic fibroblastoma) from the files of the Armed Forces Institute of Pathology were analyzed. These tumors occurred mostly in men (80%) with a median age of 50 years (range, 16 to 81 years). The lesions had a wide anatomic distribution and involved the arm (24%), shoulder girdle (19%), posterior neck or upper back (14%), feet or ankles (14%), leg (14%), hand (8%), and abdominal wall and hip (6%). The patients typically presented with a history of a painless, slowly growing mass, often of relatively long duration. The tumors ranged in size from 1 to 20 cm (median, 3.0 cm). The lesions were predominantly subcutaneous, but fascial involvement was common, and 27% of cases involved skeletal muscle. Gross examination typically showed an elongated, lobulated, or disc-shaped mass with a firm consistency and a homogeneous pearl-gray color. Histologically, the tumors often appeared well marginated on low-power examination, but most (78%) infiltrated fat or, less commonly, skeletal muscle. The lesional cells were relatively bland stellate and spindle-shaped fibroblasts separated by a collagenous or myxocollagenous matrix. Mitotic activity was absent or minimal. Some of the lesional cells had a myofibroblastic immunophenotype, as evidenced by focal reactivity for muscle-specific and alpha-smooth muscle actins. In a few cases, rare actin-positive cells were also positive for keratins. Desmin, S100 protein, and CD34 were not expressed. None of the 39 patients with follow-up (median, 11 years) developed a recurrence. Collagenous fibroma is a benign fibroblastic/myofibroblastic proliferation. The large size of some of these tumors coupled with slow growth and persistence favors a neoplastic process over a peculiar reactive proliferation. The differential diagnosis includes a variety of reactive and neoplastic fibroblastic lesions, most importantly fibromatosis and low-grade fibromyxoid sarcoma. Simple, conservative excision is the treatment of choice for collagenous fibroma.