Marcelis, Stijn

Van Damme, Sofie

Vanhoenacker, Filip

Ghent University Academic Bibliography

Case 16132 Odontogenic keratocyst of the mandibleStijn Marcelis , Sofie Van Damme  , Filip M. Vanhoenacker 1 2 1, 3, 4(1) Department of Radiology, University Hospital of Antwerp, University of Antwerp, Edegem,Belgium (2) Department of Pathology, General Hospital AZ Sint-Maarten, Mechelen, Belgium(3) Department of Radiology, General Hospital AZ Sint-Maarten, Mechelen, Belgium (4) Department of Radiology, University Hospital of Ghent, University of Ghent, Belgium University Hospital Antwerp  Head & Neck Imaging Section: 2018, Sep. 18 Published: 61 year(s), femalePatient:Clinical HistoryA 61-year old woman presented with episodes of paresthesia in the region of the left mental nerveand a slowly enlarging swelling of left mandible since 2 years.Imaging FindingsA Cone Beam Computed Tomography (CBCT) showed a large radiolucent lesion in the leftmandible with cortical breakthrough of the buccal cortex with an associated soft tissue component(Fig.1a). The mesiodistal extent was larger than the buccolingual extension.(Fig.1a) The roots ofteeth 35 and 34 are located in the cyst (Fig.1b, Fig.2). The intimate relationship of the lesion withthe mandibular canal may explain the paresthesia in the region of the left mental nerve (Fig.2).Magnetic resonance imaging (MRI) showed an intramedullary lesion in the left mandible withscalloping of the lingual cortex and breakthrough of the buccal cortex(Fig.4). The lesion wasisointense to muscle on T1-WI (Fig.3) and hyperintense on T2-WI with intralesional areas ofintermediate signal (Fig.4b). After gadolinium contrast administration, there was weak peripheralrim enhancement (Fig.5a-b). Surgical enucleation revealed a cystic lesion containing keratin. Onhistopathological examination, the cyst wall consists of keratinized squamous epithelium.DiscussionBased on the imaging and histopathologic findings, the diagnosis of odontogenic keratocyst (OKC)was made. OKC is a developmental odontogenic cystic lesion arising from additional remnants ofthe dental lamina of the jaw bones or the basal cells from the oral epithelium. OKCs represent2-11% of all odontogenic cysts, affect all ages with a peak from the 2nd-4th decade and have a maleto female ratio of 2:1[1, 2]. Clinically, most OKCs are asymptomatic but symptoms like pain,swelling and paresthesia of the lower lip can be seen in larger lesions[2, 3)]. In children, they areoften associated with basal cell naevus syndrome (NBCCS or Gorlin's syndrome), consisting ofmultiple OKCs, skin basal cell carcinomas, skeletal abnormalities and falx calcifications[2].Radiologically, OKCs are difficult to differentiate from other radiolucent odontogenic lesions. Apanoramic radiograph typically reveals a radiolucent unilocular or multilocular lesion withwell-demarcated or scalloped margins. Larger lesions tend to be more multilocular[2]. Most lesions(75%) are located in the posterior mandible with 50% occurring at the angle. Other lesions arelocated in maxilla with a possible expansion into the maxillary sinus. In 25%-40% an impactedtooth is seen and therefore it can be difficult to differentiate from a dentigerous cyst. Teethdisplacement may occur but root resorption is very rare[1]. (CB)CT shows similar features aspanoramic radiographs but (CB)CT is superior to determine lesion extension and cortical thinningor breakthrough[4]. OKC tend to grow in a mesiodistal direction while ameloblastomas usuallyshow a predominant buccal-lingual expansion[2]. On MRI, the signal may vary, whereasameloblastomas are hypo-intense on T1- and hyperintense on T2-WI[5-7]. There is a weakenhancement of the rim in OKCs whereas ameloblastoma display a nodular enhancement pattern[2,8]. Diffusion weighted imaging (DWI) can be used to differentiate between OKCs andameloblastomas. OKCs contain desquamated keratin which increases the viscosity and thereforemay cause diffusion restriction. Ameloblastomas containing proteinaceous fluid do not showrestricted diffusion[6]. In case of NBCCS, (CB)CT and MRI can be used to detect multifocality.Because imaging features may be nonspecific, histological confirmation is mandatory[2]. The cystwall is composed of a keratinized squamous epithelium. Treatment of OKCs depend on age, sizeand location of the cyst and soft tissue expansion. Treatment options are enucleation,marsupialization, curettage and osteotomy[4]. Regular follow-up for 5 years is recommended as therecurrence rate is high[1].Written informed patient consent for publication has been obtained.Final DiagnosisOdontogenic keratocystDifferential Diagnosis ListDentigerous cyst, Radicular cyst, Ameloblastoma, Lateral periodontal cyst, Odontogenic fibroma,Odontogenic myxoma (myxofibroma), Aneurysmal bone cyst, Central giant cell granulomaFiguresFigure 1 Cone Beam CT of the mandibleAxial: Large radiolucent lesion (open arrow) with breakthrough of the buccal cortex (oval).Note a soft tissue component (arrow), the precise extent is difficult to evaluate on CBCT,due to lack of soft tissue contrast. © Vanhoenacker FM, Department of Radiology, AZ Sint-Maarten, Mechelen, Belgium Area of Interest: Head and neck;  Imaging Technique: CT;  Procedure: Diagnostic procedure;  Special Focus: Cysts; Sagittal reformatted image: the roots of teeth 35 (dotted arrow) and 34 (not shown on thisimage) is located in the lesion. Cortical breakthrough (oval). © Vanhoenacker FM, Department of Radiology, AZ Sint-Maarten, Mechelen, Belgium Area of Interest: Head and neck;  Imaging Technique: CT;  Procedure: Diagnostic procedure;  Special Focus: Cysts; Figure 2 CBCT-reformatted panoramic imageLarge multilocated radiolucent lesion (arrow) with an intimate relationship with teeth 34 and35 and the left mandibular canal (dotted arrows). © Vanhoenhacker FM, Department of Radiology, AZ Sint-Maarten, Mechelen, Belgium Area of Interest: Head and neck;  Imaging Technique: CT;  Procedure: Diagnostic procedure;  Special Focus: Cysts; Figure 3 Magnetic resonance imaging (MRI) T1-weighted image without Gadolinium contrastThe lesion (arrow) is isointense to muscle (dotted arrow). © Vanhoenacker FM, Department of Radiology, AZ Sint Maarten, Mechelen, Belgium Area of Interest: Head and neck;  Imaging Technique: MR;  Procedure: Diagnostic procedure;  Special Focus: Cysts; Figure 4 Magnetic resonance imaging (MRI) T2-weighted imagesAxial T2 with fat suppression (FS): Intramedullary lesion causing slight thinning of thelingual cortex (open arrow) and cortical breakthrough of the buccal cortex (dotted arrow). © Vanhoenacker FM, Department of Radiology, AZ Sint Maarten, Mechelen, Belgium. Area of Interest: Head and neck;  Imaging Technique: MR;  Procedure: Diagnostic procedure;  Special Focus: Cysts; Coronal T2 without FS: The lesion is predominantly of high signal with intralesional areas ofintermediate signal (arrows in a and b). © Vanhoenacker FM, Department of Radiology, AZ Sint Maarten, Mechelen, Belgium. Area of Interest: Head and neck;  Imaging Technique: MR;  Procedure: Diagnostic procedure;  Special Focus: Cysts; Figure 5 Magnetic resonance imaging (MRI) before and after Gadolinium contrastAxial T1 FS before gadolinium contrast. © Vanhoenacker FM, Department of Radiology, AZ Sint Maarten, Mechelen, Belgium. Area of Interest: Head and neck;  Imaging Technique: MR;  Procedure: Diagnostic procedure;  Special Focus: Cysts; Axial T1 FS after gadolinium contrast: faint rim enhancement (arrows). © Vanhoenacker FM, Department of Radiology, AZ Sint Maarten, Mechelen, Belgium. Area of Interest: Head and neck;  Imaging Technique: MR;  Procedure: Contrast agent-intravenous; Diagnostic procedure;  Special Focus: Cysts; References[1] Chirapathomsakul D, et al. (2006) A review of odontogenic keratocysts and the behavior ofrecurrences Oral Surg Oral Med Oral Pathol Oral Radiol Endod.[2] Bernaerts A, Vanhoenacker FM, Hintjens J, Chapelle K, Salgado R, De Foer B, et al. (2006)Tumors and tumor-like lesions of the jaw: radiolucent lesions JBR-BTR.[3] Eryilmaz T, et al. (2009) Odontogenic keratocyst: an unusual location and review of theliterature Ann Plast Surg.[4] Bhargava D, et al. (2012) Keratocystic odontogenic tumour (KCOT)--a cyst to a tumour OralMaxillofac Surg.[5] Minami M, et al. (1996) Cystic lesions of the maxillomandibular region: MR imagingdistinction of odontogenic keratocysts and ameloblastomas from other cysts AJR Am J Roentgenol.[6] Sumi M, et al. (2008) Diffusion-weighted MR imaging of ameloblastomas and keratocysticodontogenic tumors: differentiation by apparent diffusion coefficients of cystic lesions AJNR Am JNeuroradiol.[7] Fujita M, et al. (2013) Diagnostic value of MRI for odontogenic tumours DentomaxillofacRadiol.[8] Konouchi H, et al. (2006) Usefulness of contrast enhanced-MRI in the diagnosis of unicysticameloblastoma Oral Oncol.CitationStijn Marcelis , Sofie Van Damme  , Filip M. Vanhoenacker 1 2 1, 3, 4(1) Department of Radiology, University Hospital of Antwerp, University of Antwerp, Edegem,Belgium (2) Department of Pathology, General Hospital AZ Sint-Maarten, Mechelen, Belgium(3) Department of Radiology, General Hospital AZ Sint-Maarten, Mechelen, Belgium (4) Department of Radiology, University Hospital of Ghent, University of Ghent, Belgium (2018,Sep. 18)  Odontogenic keratocyst of the mandible {Online}URL: http://www.eurorad.org/case.php?id=16132

Odontogenic keratocyst of the mandible

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Odontogenic keratocyst of the mandible

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