2. Case story / examination
A 15-year-old girl with a chief complaint of swelling in the right
mandibular premolar region was referred to our department. She had a
history of surgery for a congenital ear fistula. The patient first
recognized a painless mass in her mandible at 6 years of age. On this
occasion, she was referred to a local dental clinic for the treatment of
dental caries and then to our hospital for the treatment of the
mandibular tumor. Intraoral examination revealed a well-defined,
painless, elastic hard mass, measuring 17×17 mm in size, between the
right mandibular canine and first premolar (Figure 1). Panoramic
radiography showed a radiolucent area in the alveolar bone at the same
location (Figure 2). In addition, sandy calcification was observed
inside the lesion. Computed tomography (CT) revealed compressive bone
resorption of the alveolar bone between the mandibular right canine and
first premolar (Figure 3). Magnetic resonance imaging (MRI) revealed an
endophytic appearance of a well-defined enhancing mass on the right side
of the mandible on T2-weighted imaging (Figure 4).
A biopsy was performed under local anesthesia and a benign tumor with
fibroblast proliferation was diagnosed. Tumor resection was performed
under general anesthesia. The tumor was detached from the surrounding
bone surface and resected, including the periosteum. A bone depression
was observed around the tumor, and the bone surface was smooth. The
tumor was 17×17 mm in size and had a smooth surface. Histopathological
examination revealed spindle-shaped fibroblast-like cells that spread
subcutaneously. Scattered cord-like and lump-like epithelial components
were observed in the fibrous tissue near the base of the tumor (Figure
5A). No atypical cells or nuclear fission were observed. Cementum-or
bone-like calcifications were observed in the deep area of the tumor.
Epithelial components resembled Marasse’s remaining epithelial or
Hertwig epithelial sheath and were positive for cytokeratin (CK) CK19
staining (Figure 5B, C). There were no signs of post-operative
recurrence after 16 months.