A CASE OF AGGRESSIVE FIBROMATOSIS INVADED MANDIBULAR BODY ON THE PAROTID REGION

이하부에 발생한 침습성 섬유종증이 하악체에 침범한 증례 보고

Fibromatosis is benign fibroblastic proliferative lesion with abundant collagenous neo-formation located principally in the abdominal wall and in the upper and lower extremities (Masson & Soule, 1966). Wilkins and Waldron, in 1975, suggested that the title aggressive fibromatosis was a more appropriate term, reflecting the invasive characteristics of the disease. Synonyms listed were extra-abdominal desmoid, juvenile fibromatosis, aggressive infantile fibromatosis and congenital fibrosarcoma. A total of 12% of all fibromatosis arise in head and neck. Fibromatosis of the oral cavity is uncommon and is even more rare when in involve the mandibule. It is a locally aggressive fibrous tissue tumor, generally does not metastasize, but may cause considerable morbility and even death due to local infiltration. The degree of microscopic cellularity is variable, not only from tumor to tumor but also from area to area in the same tumor. Some tumors present with proliferation of mature fibroblasts and a dominating collagenous component : others may show a lack of the tumor in both types. The common histologic denominator appears to be cellular interlacing bundles of elongated fibroblasts, showing little or no mitotic activity and no pleomorphism. Mitosis are not a consistent index of malignancy when found in younger age groups. Fibromatosis still posses difficult problems of diagnosis and treatment. It is frequently recurrent and infliltrates neighbouring tissues. These lesion infliltrate widely and replace muscle, fat, and even bone with fibrous tissue of varying cellularity. Lesion representing fibromatosis in the oral cavity must be carefully evaulated by both surgeon and pathologists to ensure proper diagnosis and treatment planning. When these lesions involve bone, surgeon must be aware of the lesion's potential to perforate the cortex and expand while remaining hidden from the surgeon's view. Careful and precise clinical correlation with histologic appearance is essential to preclude misdiagnosis of fibrosarcoma yet provide surgical treatment plan that provides adequate local excision and long-term follow up. As regards cause, little is known. It is attributed to trauma or alteration in the sex hormone(Carlos, et al, 1986). Clinially, the lesion is reported to be not painful in most cases, but capable of rapid growth. The treatment is essentially surgical excision with wide margin of adjacent uninvolved tissue. Radiotherapy, hormone treatment or chemotherapy are of no use (WIkins et al, 1975 ; Majumudar and Winiarkl, 1978). We report a case of aggressive fibromatosis of 15-year-old with a lesion in the soft tissue of the parotid area that invaded the underlying bone of the mandibular body.