|Year : 2014 | Volume
| Issue : 3 | Page : 238-241
Desmoplastic fibroblastoma (collagenous fibroma) in the oral cavity
Thomas Varghese1, Karthigakannan Subramanian Pillai1, Sreenivasan Bhargavan Sarojini2, Ektah Khosla3
1 Department of Oral Medicine and Radiology, Mar Baselios Dental College, Kothamangalam, Ernakulam District, Kerala, India
2 Department of Oral Pathology and Microbiology, Mar Baselios Dental College, Kothamangalam, Ernakulam District, Kerala, India
3 Department of Pediatric Dentistry, Mar Baselios Dental College, Kothamangalam, Ernakulam District, Kerala, India
|Date of Web Publication||2-Jul-2014|
Departments of Oral Medicine and Radiology, Mar Baselios Dental College, Kothamangalam, Ernakulam District - 686 691, Kerala
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Desmoplastic fibroblastoma (DF) also known as collagenous fibroma (CF) is a rare benign soft tissue tumor that occurs in varied locations in the body. Very few cases of DF have been reported in the oral cavity. We report a case of DF in an 8-year-old boy presented as a slow-growing mass in the buccal mucosa since 6 months. Histopathology, special staining and immunohistochemistry studies suggested a diagnosis of CF. As per our knowledge of the current literature this is the seventh case reported in the oral cavity and the first report in a child.
Keywords: Collagenous fibroma, desmoplastic fibroblastoma, fibroma
|How to cite this article:|
Varghese T, Pillai KS, Sarojini SB, Khosla E. Desmoplastic fibroblastoma (collagenous fibroma) in the oral cavity. J Indian Soc Pedod Prev Dent 2014;32:238-41
|How to cite this URL:|
Varghese T, Pillai KS, Sarojini SB, Khosla E. Desmoplastic fibroblastoma (collagenous fibroma) in the oral cavity. J Indian Soc Pedod Prev Dent [serial online] 2014 [cited 2019 Jul 17];32:238-41. Available from: http://www.jisppd.com/text.asp?2014/32/3/238/135834
| Introduction|| |
Desmoplastic fibroblastoma (DF) is a rare benign slow growing fibroblastic or myofibroblastic tumor of the soft tissue first described by Evans in 1995.  As the term "fibroblastoma" may be construed as an immature or potentially malignant neoplasm, Nielsen et al.  and Hasegawa et al.  proposed the name "collagenous fibroma (CF)" as being not only more descriptive of its histological composition but also more reflective of its benign prognosis.  DF mainly affects the subcutaneous and intramuscular tissue of different parts of the body including arms, shoulders, legs, and hands. , DF shows a strong sex predilection for men and the age of occurrence is between fifth and sixth decades of life. DF is, rarely reported in oral mucosa and the site reported are palate, tongue, alveolar mucosa and buccal mucosa. ,
Clinically, the lesion presents as a painless firm, well-circumscribed, round to oval, or lobulated mass of more than 6 months duration with tumor size varies from 1 to 2 cm and oral lesions up to 6 cm have been reported. In the excised specimen, the cut surface will appear fibrous with a glistening gray-to-white aspect.  Microscopic examination shows a hypocellular soft tissue mass predominantly composed of the collagenous extracellular matrix. Tumor cells are spindle or stellate-shaped with large or oval nuclei that may contain eosinophilic nucleoli. Mitotic activity is very rare or absent and necrosis has not been identified. Binucleated cells and multinucleated giant cells may be present and fat entrapment is also possible, vessels are often imperceptible due to the surrounding collagenous stroma. , Conservative marginal excision appears to be curative and no recurrence or metastasis is reported.
| Case Report|| |
An 8-year-old boy was brought by his parents to the Department of Oral medicine and Radiology of Mar Baselios Dental College, Kothamangalam, Kerala, India with the complaint of a swelling, which they have noticed in the left buccal mucosa since the last 6 months.
His medical and family history was noncontributory. No abnormalities were detected on general, systemic and extra oral examination. No traumatic event or habit could be associated with the lesion. Intra oral examination revealed a swelling on the right buccal mucosa extending to buccal sulcus in the region of a grossly decayed 84, 85, posterior to the normal buccal frenum. It measured 3 cm × 2 cm in size and the overlying mucosa appeared to be normal [Figure 1].
On palpation, the swelling was nontender, firm to elastic in consistency and freely mobile. It was firm to elastic in consistency, compressible, and nonreducible. It did not exhibit any visible or palpable pulsation.
An intra-oral periapical radiograph of the region revealed the root stump of 85 and deep caries in 84. Root resorption involving 84 and 85 was seen along with erupting 44 and 45. There was no evidence of any periapical or other osteolytic lesions [Figure 2].
By correlating the history and clinical findings a provisional diagnosis of a benign connective tissue neoplasm was made. The differential diagnosis considered were fibroma, fibrolipoma, neurofibroma, myoblastoma or an adenoma of the minor salivary gland. The lesion was surgically excised. The tissue was submitted for histopathologic examination, and the routine hematoxylin and eosin stained sections showed a circumscribed mass comprised of fibrous connective tissue, the connective tissue exhibited thick bundles of collagen fibers, which were hyalinized in many foci in association with sparse stellate and spindle-shaped fibroblasts. Few vascular spaces were also seen [Figure 3]. Deeper areas of the section show inclusion of adipose tissue from the underlying submucosa. Van Gieson special staining of the tissue was done and areas of the connective tissue with thick bundles were positive for collagen (red) [Figure 4].
The histopathological differential diagnosis considered were reactive fibrous proliferations, fibromatosis, tumors of myogenous and neurogenic origins. Immunohistochemically the lesional cells were negative for S100 and smooth muscle actin (SMA). Based on the clinical, histological and immunohistochemical findings a diagnosis of DF was made. The patient was recalled after 1 week for suture removal and the surgical site showed excellent wound healing [Figure 5]. The patient is under observation and has been reviewed periodically for the last 1 year with no evidence of any recurrence of lesion.
| Discussion|| |
Desmoplastic fibroblastoma or CF is a rare benign soft tissue tumor, frequently found in several locations in the body but its occurrence is extremely rare in the oral cavity. Literature review of DF showed the intra oral site of occurrence as three in the palate, one on the tongue, one in the alveolar mucosa and one in the buccal mucosa.  In our case the lesion involved the buccal mucosa and resembled a hyperplastic buccal frenum, this report is the second case occurring in the buccal mucosa. DF has a male predominance with peak incidence in the fifth and sixth decade of life, whereas in the intraoral location among the six cases reported five were reported in females. The present case is the first one reported in an 8-year-old boy. The tumor usually presents in the subcutaneous tissue or skeletal muscle and is seen as a solitary, mobile painless mass of more than 6 months duration.  On gross examination, the lesion appeared as an oval mass with a resilient and fibroelastic consistency. The clinical and histopathological features of our case were consistent with the criteria proposed by Evans for diagnosis of CF. In our case the lesional tissue was positive for collagen and negative for muscle when stained with the trichome stain; (Van Gieson) there by excluding tumors of myogenous origin. When soft tissue proliferations with collagen production were considered, reactive fibrous hyperplasias like traumatic fibroma or inflammatory fibrous hyperplasia has to be considered,  but in our case no traumatic event was present and there was lack of inflammatory cell infiltration in the tissue section, which ruled out the possibility of any fibrous hyperplasia due to trauma from the oral cavity. Radiographic examination showed that there were no periapical or other osteolytic lesions on the adjacent jaw bone excluding the possibility of an inflammatory fibrous hyperplasia from an odontogenic infection. According to Evans, DF represents a true neoplasm given that no inciting event or no specific cause for a reactive fibrous proliferation could be microscopically identified. Furthermore, a cytogenetically abnormal clone involving the 11q 12 break point was detected in some cases corroborating with the neoplastic nature of DF. 
When fibrous tumors were considered as differential diagnosis, the possibility of the tumor being juvenile hyaline fibramatosis had to be ruled out. , They are formed by fibroblast cells with areas of amorphous hyaline material. Differentiating between fibramatosis and CF only by microscopic examination is difficult due to their histologic similarity. Fibramotosis are locally aggressive infiltrating fibroblastic tumors with frequent recurrences. However, our case presented as a benign, well-defined, circumscribed mass with no attachment to the overlying or underlying structures.  Another collagen producing tumor to be considered in the differential diagnosis is myofibroma. Myofibromas are typically more cellular with SMA positive spindle shaped myofibroblasts.  The lesional tissue of the present case was sparsely cellular with thick bundles of collagen fibers and the tumor cells were SMA negative. Solitary neurofibroma is a neurogenic collagen producing tumor. They usually present with thin spindle shaped cells with wavy nuclei intimately associated with wire like strands of collagen in a myxoid matrix. Rarely can these tumors be cellular or present with thick bundles of collagen fibers resembling CF, but the tumor cells in the present case was S100 negative ruling out a tumor of neurogenic origin. 
There are some questions as to whether DF represents a neoplasm or a reactive condition. According to Evans and Neilson et al. DF represents a neoplasm because no inciting event was clinically mentioned, and no specific cause of a reactive fibrous proliferation was microscopically identified. The current treatment of choice for DF is total surgical excision, and the prognosis is good. No patient to date has experienced tumor recurrence or metastasis in several follow-up studies. Our patient was treated with complete excision and he has had no recurrence or metastasis during the 1 year follow-up.
| Conclusion|| |
Desmoplastic fibroblastoma is a slow growing, benign fibroblastic or myofibroblastic soft tissue tumor occurring in subcutaneous or intramuscular tissue with wide anatomic distribution. A chromosomal abnormality in the same band of the long arm of chromosome 11, more specifically, a rearrangement of 11q12 has been associated with DF. No traumatic event or habit could be associated with the lesion. Literature points to a male preference in the fifth and sixth decade of life. A maximum size of 20 cm in skin and 6 cm in the intraoral location has been reported. Intraoral occurrence is rare with only six cases reported occurring as three in the palate, one in tongue and alveolar mucosa and including the present case two in the buccal mucosa. Five of the above intraoral lesions occurred in females. The present case is the second case reported in a male and first report in a child. Histopathological examination, special staining and immunohistochemical studies help at arriving at a correct diagnosis. Treatment of choice is total surgical excision and has an excellent prognosis with no recurrence is expected.
| Acknowledgment|| |
We would like to acknowledge Dr. Giju Baby George MDS, Dr. Sujeev N, Mar Baselios Dental College, Kothamangalam for his invaluable help in case diagnosis and Dr. Leena Johnson for critical revision of the article manuscript.
| References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]