Intraosseous mucoepidermoid carcinoma: a review of the diagnostic imaging features of four jaw cases

Abstract

The purpose of this case series is to present the common features of intraosseous mucoepidermoid carcinoma (IMC) of the jaws in plain film and CT imaging. Two oral and maxillofacial radiologists reviewed and characterized the common features of four biopsy-proven cases of IMC in the jaws in plain film and CT imaging obtained from the files of the Department of Oral Radiology, Faculty of Dentistry, University of Toronto, Toronto, Canada. The common features are a well-defined sclerotic periphery, the presence of internal amorphous sclerotic bone and numerous small loculations, lack of septae bordering many of the loculations, and expansion and perforation of the outer cortical plate with extension into surrounding soft tissue. Other characteristics include tooth displacement and root resorption. The four cases of IMC reviewed have common imaging characteristics. All cases share some diagnostic imaging features with other multilocular-appearing entities of the jaws. However, the presence of amorphous sclerotic bone and malignant characteristics can be useful in the differential diagnosis.

Figure 1

(a) Axial and (b) coronal. CT bone windows of Case 1 show the epicentre of the lesion at the root apex in the right maxillary alveolar process. The lesion has a well-defined, sclerotic border and a mixed radiolucent–radiopaque internal pattern. The radiopaque pattern consists of multiple, small loculations measuring less than 8 mm, a few of which are bordered by sclerotic septae (straight arrow), and many of which lack such borders (curved arrow). The internal structure also consists of amorphous sclerotic bone (arrowhead). The palatal cortex is expanded and perforated with soft-tissue extension. The floor of the maxillary sinus is superiorly displaced and breached

Figure 2

Axial CT bone window of Case 2 shows a well-defined sclerotic lesion in the left mandibular body with a sclerotic periphery (straight arrows). The internal pattern is very sclerotic and consists of multiple small loculations bordered by sclerotic septae (arrowhead). These small loculations are in turn surrounded by larger loculations. The buccal cortex demonstrates cystic expansion and perforation (curved arrow)

Figure 3

(a) Panoramic film, (b) lateral occlusal film, (c) specimen film and (d) photomicrograph of a haematoxylin and eosin-stained slide of a section of specimen (2×). Case 3 shows a well-defined, sclerotic border surrounding a mixed radiolucent–radiopacity that consists of amorphous sclerotic bone (straight arrow) and multiple loculations with (arrowhead) and without (curved arrow) sclerotic border. The mandibular canal, the second and third molars are displaced. The distal root of the second molar is resorbed. The section of specimen shows cystic components of mucoepidermoid carcinoma invading the cancellous bone in the mandible. The residual cancellous bone (black straight arrows) between the neoplastic elements likely represents the sclerotic septae (arrowhead) dividing the loculations on film

Figure 4

(a) Axial and (b) coronal. CT bone windows of Case 4 show a well-defined mixed radiolucent–radiopacity with a sclerotic periphery in the left maxilla that has crossed the midline. The internal amorphous sclerotic bone (straight arrow) and loculations are once again demonstrated. A few of the small loculations are not bordered by sclerotic septae (arrowhead). The buccal cortex exhibits considerable cystic expansion and perforation (curved arrow). The lesion has also displaced the molar buccally

Figure 5

Axial CT bone window of a recurrent ameloblastoma of the posterior left maxilla shows similar imaging features of internal amorphous sclerotic bone (straight arrow) and small loculations (curved arrow) without and with sclerotic septae (arrowhead), when compared with the cases of intraosseous mucoepidermoid carcinoma presented