Aggressive fibromatosis of the mandibular region: A report of an infant case

Abstract

A case of aggressive fibromatosis of a 29-month-old girl is presented. Her mother noticed swelling in the right mandibular region about two months before her first visit to our hospital. At the first visit, the intraoral examination revealed a mass in the vestibule of the right lower molar region. The lesion was elastic-soft in consistency and showed slight tenderness. The covering mucosa was intact. Under a tentative diagnosis of lymphangioma, the lesion had grown rapidly at the follow-up. CT scan revealed a well-demarcated mass with a resorption of the mandibular bone, and the root of right lower D was affected by the lesion. On MRI, the lesion was of low intensity in the T1 enhanced image and of medium intensity in the T2, without intensity regression on the fat-regression T2 image. A biopsy specimen showed the proliferation of spindle-shaped cells with an interlacing bundle pattern and the appearance of hyalinized collagen fibers. The pathological findings were suggestive of aggressive fibromatosis. She underwent excision of the tumor, curettage of underlying bone surface, and extraction of right lower D under general anesthesia. Post-operative course has been uneventful without local recurrence for 3 years and 6 months.