|Year : 2013 | Volume
| Issue : 1 | Page : 23-26
Aggressive fibromatosis of the infratemporal region
Samir Ahmed1, RC Pramod2, Sharan J Shetty3, Pramod S Ingaleshwar4
1 Department of Oral Pathology and Microbiology, KMCT Dental College, Calicut, Kerala, India
2 Department of Oral Pathology and Microbiology, School of Dental Science, Krishna Institute of Medical Sciences University, Karad, Maharashtra, India
3 Department of Oral Pathology and Microbiology, A. J. Institute of Dental Sciences, Mangalore, Karnataka, India
4 Department of Oral Pathology and Microbiology, P. M. Nadagouda Memorial Dental College and Hospital, Bagalkot, Karnataka, India
|Date of Web Publication||14-Jan-2014|
KMCT Dental College, Calicut, Kerala
Source of Support: None, Conflict of Interest: None
Aggressive fibromatosis (AF) is identified to involve subcutaneous tissue, muscle, and neurovascular structures. Though the tumor is of bland histological features and low mitotic activity, it has a aggressive infiltrative growth pattern along tissue planes and invasion of adjacent tissue. Here we present a rare case report of a 19-year-old man with AF of the infratemporal region. Tumor growth was rapid and involved the infratemporal region. Biopsy was taken and in histological examination showed a tumor consisting of spindle-shaped fibroblast cells proliferating in fascicles within a collagenous stroma with rare atypia. Microscopically, a diagnosis of AF was rendered.
Keywords: Aggressive fibromatosis, infratemporal region, fibrosarcoma
|How to cite this article:|
Ahmed S, Pramod R C, Shetty SJ, Ingaleshwar PS. Aggressive fibromatosis of the infratemporal region. Dent Med Res 2013;1:23-6
| Introduction|| |
Aggressive fibromatosis (AF) is a non-metastasizing tumor-like fibroblastic growth. It involves voluntary muscle as well as aponeurotic and facial structures. The pathogenesis of its involvement is unknown. The tumor is recognized to have a strong tendency for aggressive infiltrative growth and local recurrence.  Fibromatosis of head and neck makes up 10-12% of reported cases of extra-abdominal fibromatosis. The supraclavicular area is the most commonly affected with only very few cases have been reported in the infratemporal region.  Here we present a rare case report of a 19-year-old man with AF of the infratemporal region.
| Case Report|| |
A 19-year-old patient visited with a chief complaint of swelling in the right mid face region since 4 months. Initially the swelling present over the right cheek was insidious in onset and had gradually increased in size. He also complained of pain in the right cheek while lying down and relieved on sitting. Family, drug, and personal history were noncontributory.
Swelling extended superiorly from below the infraorbital rim to ala of the nose posteriorly till tragus of the ear. Inferiorly till the cheek not involving the inferior border of the mandible. Skin overlying the swelling did not show any abnormality. Pulsations were not seen. The size was about 5 × 5 cm with ill-defined borders [Figure 1] and [Figure 2]. On palpation the swelling was tender with increased temperature, soft in consistency, and no fluctuations were present. It was not fixed to the overlying skin or underlying structures. Intraoral examination revealed firm consistency in the maxillary tuberosity area with obliteration of buccal vestibular space.
Computerized tomography (CT) showed an isodense soft tissue lesion in the right infratemporal fossa and slight extension to right maxillary tuberosity region [Figure 3]. Macroscopically the specimen had a well-defined border and measured about 3 × 5 cm in diameter [Figure 4]. Microscopy revealed cellular areas with predominantly spindle-shaped fibroblasts cells proliferating in fascicles. Under high power spindle cells were plump and had vesicular nuclei. Few atypical spindle cells were also seen [Figure 5]. Split-like vascular spaces and nerve tissues were also seen [Figure 6]. A final diagnosis of AF of the infratemporal region was rendered. The patient underwent surgical resection with wide surgical margins. Presently the case is under follow-up for the past 2 years and there is no evidence of recurrence.
|Figure 3: Computerized tomography showed an isodense soft tissue lesion in the right infratemporal fossa and slight extension to right maxillary tuberosity region|
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|Figure 4: Macroscopically the specimen had a well-defined border and measured about 3 × 5 cm in diameter|
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|Figure 5: Microscopy revealed cellular areas with predominantly spindle-shaped fibroblasts cells proliferating in fascicles|
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| Discussion|| |
AF is a non-metastasizing, tumor-like fibroblastic growth. It involves voluntary muscle as well as aponeurotic and facial structures. The pathogenesis of its involvement is unknown. The most common sites for the involvement of AF are the shoulder girdle, the thigh, and gluteal region of growing adults and is a very rare finding of the oral or paraoral structures.  AF belongs to a sizeable group of the so-called "miscellaneous locally aggressive fibrous lesions". They are non-metastasizing and should always be differentiated from the well-differentiated type of fibrosarcoma. There always remained a confusion of these benign but locally aggressive lesions with fibrosarcomas and only recently the pathologists have been able to differentiate these lesions with affirmation.  Despite these lesions are benign they can damage surrounding structures causing organ dysfunction. Histological features resemble low grade fibrosarcomas, but locally they are aggressive and have a strong tendency to recur even after complete resection.  Mackenzie has defined the term fibromatosis as an infiltrating fibroblastic proliferation without any feature of unequivocal neoplasia. The prefix "aggressive" is still chosen because it gives a better sense of tumor biology with its astonishing local gruesome behavior. Bewilderment still remains and some consider the aggressive form to be a low-grade fibrosarcoma. 
Even though the etiology of AF is unknown, many studies have supported to be a connective tissue disorder.  The lesion has been associated with hereditary syndromes like Gardner's syndrome. Based on X-chromosome inactivation pattern, AF appear to be monoclonal disorder, inactive of a neoplastic rather than an inflammatory fibrous reactive process.  Fibromatosis involving the head and neck region are roughly 10-12% of the reported cases. It may exhibit both rapid growth and visceral involvement. Spontaneous regression has been described, but rare tumors mimic a malignancy in their tendency to occur locally.  Fibromatosis and fibrosarcoma may occur in the same age group and in the same location, and hence, clinical considerations are difficult in differentiating between the two tumors. It is difficult to separate fibromatosis from well-differentiated fibrosarcoma, especially in infants and juveniles when fibromatosis is characterized by higher mitotic rates than in adults.  The tumor is known to originate from the facial planes of soft tissues but does not metastasize. It is also known to involve subcutaneous tissue, muscles, and neurovascular structures. However, bone involvement is a rare finding.  Fibrosarcoma is detectable histologically by the presence of increased cellularity, increased mitotic activity, larger nuclei with significant chromatin clumping, and thin collagen bundles. The role of immunohistochemisty is limited due to positivity for smooth muscle actin (SMA) and vimentin in both fibromatosis and fibrosarcoma.  Hence in our case, immunohistochemistry (IHC) was not carried out.
The pathologist may be more inclined to the anatomical location of the lesion, sex, and the clinical behavior of the tumor than the histologic appearance in rendering the diagnosis since the histologic features may overlap. The diagnosis and the management of fibromatosis is always a source of concern.  Fibromatosis is divided into two major groups with several subdivisions based on the clinical presentation, patient age, and natural history. Based on anatomic location, it can be divided into superficial and deep subtypes. The superficial fibromatoses are usually small, slow-growing lesions that rarely involve deep structures. The deep fibromatosis are rapidly growing lesions that are large in size and have a higher tendency to recur after treatment, hence the term "aggressive fibromatosis". 
The treatment of choice may involve surgery, radiotherapy, and/or systemic approaches. Generally surgery was considered as the main treatment for AF, its goal preferably being a complete resection with histologically free margin. Postoperative radiotherapy could be used in cases with positive margins after surgery to avoid mutilating surgery in cases of inoperable or inaccessible disease. It has been reported that postoperative radiotherapy hoist local disease control to a level similar to that of complete resection, but is associated with a relatively high rate of complications. In cases of locally-advanced disease, systemic treatment may be indicated. These tumors warrant a wait-and-watch strategy. Their natural history is often characterized by lengthy periods of stability or even regression, considering to treat only patients with progressing or symptomatic disease.  Recent reports have indicated that there may be a place for adjuvant medical therapy with nonsteroidal anti-inflammatory drugs, vitamin K1, warfarin, antiestrogens, and testolactone, either alone or in combination. 
| Conclusion|| |
AF appears a locally infiltrative process composed of mature fibroblasts and collagen, lack of cellular atypia, or abnormal mitosis. It is histologically benign but biological behavior similar to a low grade malignant tumor. Although CT appearance is nonspecific, it is useful in assessment of bony involvement. The treatment choice of AF is wide surgical excision. However, the result of adjuvant therapy including surgery with radiation or chemotherapy may be of benefit.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]