An unusual Pindborg\'s tumour

Clinical History

A 45-year-old female patient complained of a right-sided swelling of the jaw progressively increasing in size and causing facial asymmetry.

Imaging Findings

1. Panoramic radiograph shows a multilocular mixed lesion extending from the distal surface of the mandibular second molar along the full length of the ramus to the coronoid process and coronoid notch, sparing the head of condyle and angle of mandible. There are multilocular spaces with multiple small densities highly suggestive of Pindborg’s tumour.

2. PA skull shows complete obliteration at the inferior border of the mandible and condyle extending mesially to the floor of the right maxillary sinus.

3. CT shows an ill-defined expansile osteolytic lesion with soft tissue component and multiple calcified densities in the body, alveolar process, coronoid, condyloid and ramus of the mandible on the right side. The soft tissue component is extending into the infra-temporal fossa causing infiltration of the temporalis muscle. The lateral pterygoid muscle is compressed and displaced medially. The lesion is causing marked thinning and remodelling of the posterior maxillary sinus wall. It is infiltrating the retromolar trigone and upper gingivo-buccal sulcus.

Discussion

Odontogenic tumours comprise a diverse group of exceptional lesions derived from epithelial elements of the tooth-forming apparatus that account for about 1% of all jaw tumours [1]. The calcifying epithelial odontogenic tumour (CEOT) was first described by Pindborg as a distinct entity in 1955 [2]. It is an asymptomatic benign slow expanding locally invasive tumour of the jaws accounting for approximately 1% of all odontogenic tumours [3, 4]. It is most often encountered between the age of 8 and 92 years with the peak occurrence in 40 years of age irrespective of gender [5]. CEOT is classified as intraosseous or extraosseous. The extraosseous variant has a predilection for the anterior gingival location. Clinically it appears as a sessile mass capable of destroying the underlying bone. The intraosseous type is more commonly found in the mandibular posterior region. More than half of these are associated with an impacted tooth [6]. Radiographically, the intraosseous lesion appears as a radiolucency. However, as the lesion ages, calcium salts are deposited and simultaneously bony erosions occur. As a result, the lesion becomes increasingly radio-opaque. In later stages of development, the lesion is often mixed radiolucent/radio-opaque giving a characteristic ‘driven snow’ appearance on the radiograph. Furthermore, the lesion may be unilocular or multilocular in appearance. However, the multilocular variant is more common. Thoma reported that 65% lesions out of his 67 cases of Pindborg tumour were radiographically mixed (radiolucent/radio-opaque) type followed by 32% complete radiolucent and 3% radio-opaque[7]. Microscopically CEOT is composed of polyhedral epithelial cells, the presence of an amorphous, homogeneous, eosinophilic, amyloid-like material and foci of calcification in the form of lamellar, concentric structures known as Liesegang’s rings [5]. The differential diagnosis includes adenomatoid odontogenic tumour, calcifying odontogenic cyst, dentigerous cyst, ameloblastic fibro-odontoma and odontoma [4, 8]. Calcifying epithelial odontogenic tumour is less aggressive than ameloblastoma, although cases of malignant transformation have been reported [9].

Differential Diagnosis List

Final Diagnosis

Calcifying epithelial odontogenic tumour

URL:	https://www.eurorad.org/case/12531
DOI:	10.1594/EURORAD/CASE.12531
ISSN:	1563-4086