Massive odontoameloblastoma arising in the maxilla: a case report

Abstract

Introduction: Odontoameloblastoma is an extremely rare mixed odontogenic tumor with both epithelial and mesenchymal components. The term odontoameloblastoma first appeared in the 1971 World Health Organization classification (Pindborg JJ., et al.) and is defined as "a neoplasm that includes odontogenic ectomesenchyme in addition to odontogenic epithelium that resembles an ameloblastoma in both structures and behavior." Because of the aggressive nature and risk of recurrence of the tumor, complete resection is essential. In this report, we describe an extremely rare case of a patient with massive odontoameloblastoma arising in the maxilla and occupying maxillary sinus.

Case presentation: In 2013, an 11-year-old Japanese boy was referred to our department for a painless and large mass of the right maxillary region. A panoramic X-ray showed a unilocular cystic lesion in the right maxilla containing a calcified mass in the lesion associated with an impacted tooth. Computed tomography showed a cystic lesion that included calcified structures and measured 3.6×3.1×2.7 cm. In 2013, the patient underwent tumor extirpation combined with impacted tooth extraction. The histopathological diagnosis was an odontoameloblastoma. No recurrence was noted 27 months after the operation.

Conclusions: The patient has undergone postoperative occlusal guidance and functional orthodontic treatment, and his postoperative condition is excellent. However, postoperative recurrence or malignant transformation can occur in cases of odontoameloblastoma, and close long-term follow-up will be continued for our patient.

Fig. 1

An unilocular cystic lesion in the right maxilla containing calcified mass in the lesion associated with impacted tooth (arrow)

Fig. 2

Computed tomographic images. a Axial view computed tomographic image showing a cystic lesion of size 3.6×3.1×2.7 cm that included calcified structures. b Horizontal view computed tomographic scan showing right maxillary bone expansion (arrows)

Fig. 3

Intraoperative view showing extirpation of the tumor arising in the maxilla (arrow)

Fig. 4

Surgical specimens

Fig. 5

a Histopathological image (hematoxylin and eosin stain, original magnification ×100). A histological examination indicated the presence of a mixture of dentin and enamel with a radial structure. b, c Histopathological images (hematoxylin and eosin stain, original magnification ×200). A palisade arrangement of cylindrical cells was seen in the margin of the odontogenic epithelial-like cell structures, and stellate cells had proliferated in the alveolar structures