Glandular Odontogenic Cyst of the Mandible: A Case Report and its Potential Diagnostic Pitfalls
Pornpop Rattana-arpha, Ploi Yongvanijchit, Ekarat Phattarataratip
A glandular odontogenic cyst is a rare odontogenic cyst of the jaws, which demonstrates a locally aggressive behavior with high propensity to recur. Its diagnosis relies on several key histopathologic features, which are not entirely specific and can be identified in other benign as well as malignant jaw lesions. This report presents a case of 49-year old female with a large glandular odontogenic cyst of the anterior mandible. The lesion was originally diagnosed as a lateral periodontal cyst upon incisional biopsy. The clinical, radiographic, histopathologic features and main differential diagnoses of glandular odontogenic cyst are discussed to avoid its potential diagnostic pitfalls.
Keywords: Differential Diagnosis; Histopathology; Lateral Cyst; Mandible; Odontogenic Jawbone Cyst; Periodontal Cyst.
Pornpop Rattana-arpha, Ploi Yongvanijchit, Ekarat Phattarataratip. Glandular Odontogenic Cyst of the Mandible: A Case Report and its Potential Diagnostic Pitfalls. International Journal of Oral & Maxillofacial Pathology; 2013:4(2):34-39. ©International Journal of Oral and Maxillofacial Pathology. Published by Publishing Division, Celesta Software Private Limited. All Rights Reserved.
Received on: 29/01/2013 Accepted on: 04/05/2013
Glandular odontogenic cyst (GOC) is relatively a new entity. It was first described in 1987 by Padyachee and Van Wyk1, as a “sialo-odontogenic cyst”. A year later, Gardner et al.2 reported eight additional cases and introduced the now widely accepted term, “glandular odontogenic cyst”. GOC was later listed in the histologic typing of odontogenic tumors by the World Health Organization (WHO) in 19923. Several other names were formerly used to entitle GOC in the literature, including the polymorphous odontogenic cyst4 and the mucoepidermoid odontogenic cyst.5 Histopathologically GOC is composed of a thin connective tissue wall, lined by an odontogenic epithelium primarily of stratified squamous cell type. Its lining epithelium characteristically contains intraepithelial mucin pools, mucous cells and nodular thickenings of epithelial cells. In addition, the superficial layer of the epithelium is often lined by ciliated cuboidal epithelial cells.2
The diagnosis of GOC carries clinically important attributes. It represents the locally aggressive jaw cyst with a high recurrence potential.6 GOC is also notable for showing some overlapping microscopic features with other benign and malignant jaw lesions, particularly the lateral periodontal cyst (LPC),7,8 botryoid odontogenic cyst (BOC),9 other odontogenic cysts with mucous prosoplasia,10 and central low-grade mucoepidermoid carcinoma (MEC).11,12 This sometimes leads to problems in diagnosis and treatment selection. In the present study, we report a case of GOC of the mandible, which was originally misdiagnosed as BOC. Its clinical-pathologic features as well as microscopic differential diagnosis are also discussed.
A 49 year-old Thai woman presented to a hospital with a complaint of painless swelling of her chin and lower anterior gingiva. The swelling was noticed five months prior and has slowly increased in size since. In addition, she noted the gradual shift and tenderness of the mandibular right lateral incisor. The patient denied any medication use and systemic conditions except seasonal allergy. Extraoral examination revealed a facial asymmetry with slight expansion of the right anterior mandible. Neither cervical lymphadenopathy nor sign of inflammation was noted (Figure 1a). Intraorally, a bony hard swelling was detected on the lower labial vestibule, extending from the mandibular left central incisor to the right canine. The expansion was more pronounced on the facial surface than that on the lingual surface. The overlying oral mucosa was intact. Upon palpation, crepitation was discerned on the facial surface with a small area of perforation inferior to the mandibular right central and lateral incisors. The mandibular right central
incisor, lateral incisor and canine were displaced and all lower anterior teeth were slightly mobile. All teeth were vital (Figure 1b, 1c).
Panoramic and occlusal radiographs demonstrated a 3 x 5.5 cm well-defined unilocular radiolucency with corticated, scalloped border. The lesion extended in the medio-lateral dimension from the mesial aspect of mandibular left canine to the distal aspect of right second premolar, and in the supero-inferior dimension from the alveolar crest to the lower cortex of the mandible. However, the lower border of mandible was still intact (Figure 1d). The clinical differential diagnoses included keratocystic odontogenic tumor (KCOT), ameloblastoma, and the less common lesions, such as central giant cell granuloma (CGCG) and GOC. The incisional biopsy was performed on the area of bony perforation. Histopathologic examination revealed small fragmented pieces of thin cystic lining consisting of non-keratinized stratified squamous epithelium with focal nodular thickenings. No mucous cells or intraepithelial mucin pools were identified. Deprived of radiographs available for evaluation at the time, the diagnosis of “consistent with BOC” was made.
One month later, a complete enucleation with curettage of the lesion was performed under local anesthesia. The mandibular right lateral incisor was extracted. During the surgical procedure, the thin and friable cystic wall was noted, causing difficulties in removing the entire tissue from the surrounding bone. In addition, the soft tissue lining was not present in some areas of the bony cavity. As a result, the specimen grossly consisted of multiple small strip-like pieces. Microscopic examination revealed several pieces of cystic wall lined by a thin uniform layer of stratified squamous epithelium with a superficial layer of cuboidal epithelial cells. Also notable were scattered mucous cells, intraepithelial microcysts containing mucin pools, focal plaque thickenings as well as distinctive whorlings of the lining epithelium (Figure 1e,1f). The mucous cells and mucin pools were positive to mucicarmine stain. Therefore, the final diagnosis of GOC was rendered.
Continued patient follow-up showed properly healed alveolar bone. The alignment of the lower anterior teeth was improved. However, both mandibular central incisors became non-vital and therefore required root canal treatments. Patient is currently subjected under a long-term follow-up and no recurrence was seen in an 18-month period after treatment.
GOC is a rare entity, representing only 0.012 - 0.2% of all odontogenic cysts of the jaws.13,14 Being different from most jaw cysts, GOC demonstrates a locally aggressive nature with the recurrence rate ranging from 21 - 55%, depending on the treatment selection.11,15-19 It can be found in patients with a wide age range; however, the mean age at presentation is 51 years and the majority of cases are in their 5th - 7th decades of life.20 A slight male predilection was noted with a male-to-female ratio of 1.3:1.21
GOC occurs predominantly on the anterior mandible.22 Most patients present as painless swellings of the affected areas.23 Radiographically, it may present as a unilocular or multilocular radiolucent lesion with a well-defined corticated border.22,24,25 Peripheral sclerotic rim, scalloping, cortical perforation, erosion/thinning of cortical plates, root resorption and displacement of involved teeth may also be noted.18,25,26 The clinical and radiographic presentations of the present case conform to the usual GOC descriptions. However, these features are far from definitive. The clinical differential diagnoses also include KCOT, ameloblastoma and CGCG. These lesions are more common than GOC. They can be found on the anterior portion of the mandible, showing a corticated and/or scalloped border. KCOT and CGCG in particular often show minimal bucco-lingual expansion, compared to their antero-posterior extensions as noted in this case.
Histopathologic diagnosis of GOC can be problematic. The distinct similarities in microscopic features are noted among GOC and other lesions such as LPC, BOC, radicular or dentigerous cysts with mucous prosoplasia and central MEC.21 LPC shows characteristics of a thin non-keratinized epithelial lining with focal plaque thickenings containing glycogen-rich epithelial cells. BOC, a variant of LPC, also shows the identical type of cystic lining but is multicystic in nature. These features are also in common with GOC.27,28 However, the diagnosis of GOC requires additional features, including the superficial layer of ciliated epithelium, intraepithelial microcysts
and mucous cells.29,30 Therefore, it is important to identify these features in order to differentiate GOC from either LPC or BOC. The incisional biopsy specimen of the present case showed the typical cystic lining of BOC as described above. Without intraepithelial mucin pools or mucous cells being identified in the limited tissue submitted, this led to a misdiagnosis of BOC. Therefore, we strongly advocate giving comments to clinicians regarding the overlapping microscopic features among these lesions and that the diagnosis should always be confirmed from the surgical excision specimens.
Figure 1: The extraoral photograph revealed a facial asymmetry with slight expansion of right anterior mandible (a). Intraoral examination revealed a bony-hard swelling of the anterior mandible with displacement of mandibular right lateral incisor (b).The buccal expansion is more pronounced than the lingual expansion (c). A cropped panoramic radiograph showing a well-defined unilocular radiolucency with corticated and scalloped border (d). The photomicrograph showing a cystic wall lined by a thin uniform layer of stratified squamous epithelium with a superficial layer of eosinophilic cuboidal cells. Scattered mucous cells and intraepithelial microcysts containing mucin pools and focal plaque thickening with whorling of epithelial cells are also noted (e) (Hematoxylin and eosin stain, original magnification x 400) (f) (Hematoxylin and eosin stain, original magnification x 200)
In addition, in our experience, the radiographic presentations of LPC, BOC and GOC are rather different. LPC is typically a small unicystic lesion with most being less than one centimeter in size. It tends to locate between and displace roots of two adjacent
teeth. BOC is a variant of LPC which shows multicystic pattern. In contrast, GOC can be both unicystic and multicystic; however, it often produces a significant bony expansion, involving multiple teeth. Therefore, when dealing with the limited tissue specimens such as those from incisional biopsies, careful examination of radiographs prior making definitive diagnoses of certain ambiguous cases proves crucial.
Beside the LPC and BOC dilemma, a number of odontogenic cysts; particularly dentigerous cyst and radicular cyst microscopically may show mucous prosoplasia or contain ciliated epithelial cells within their cystic linings.31 These changes sometimes cause confusion and lead to an over diagnosis of GOC. In these types of lesions, it should be noted that the nodular plaque-like thickenings as well as extensive formation of intraepithelial microcysts filled with mucin should not be present. Therefore, it is important to thoroughly evaluate for these characteristic features before making a diagnosis of GOC.
Furthermore, perhaps the most important lesion on the differential diagnosis list of GOC is the intraosseous MEC due to its clinical implications. Intraosseous MEC is a malignancy with potentials for recurrence and metastasis. It is believed to arise from the epithelial lining of odontogenic cysts following a mucous prosoplasia.32 Most intraosseous MECs of the jaws are low-grade lesions and may be mistaken for GOC or vice versa. The cystic structures and mucous cells are prominent features in both lesions. However, the nodular epithelial thickenings and whorlings as well as the superficial layer of ciliated epithelial cells are not typical of MECs. Likewise, GOC should not demonstrate areas of solid growth of epidermoid and/or intermediate cells as those in MECs.
Several studies proposed the use of immunohistochemistry to distinguish between GOC and MEC. For example, Kaplan et al.33 found that GOC showed a lower p53 immunoreactivity but significantly higher Ki-67 proliferative index than MEC. Immunohistochemical study of p53 and Ki-67 in the present case also showed stainings corresponding to those of Kaplan et al.33 The p53 and Ki-67 labelling indices were 2.82 and 4.55, repectively (Figure 2). In addition, Pires et al.34 evaluated cytokeratin (CK) profiles of GOC and MEC and found that their expressions of CK18 and CK19 were significantly differed and could be useful in the differential diagnosis. Moreover, Vered et al.35 found the increased maspin (mammary serine protease inhibitor) expression in MEC but not in GOC.
Figure 2: The photomicrograph of Immunogistochemically stained p53 (a) and Ki-67 (b) showing scattered positive cells in GOC lining. (Original magnification x 200)
Various treatment modalities have been recommended for GOC patients depending on the patient status, location of the lesion and clinicians’ view. Several authors advised the conservative approaches, such as enucleation and curettage with or without applying Carnoy’s solution.36 However, due to its high recurrence rate, others recommended marginal resection37 or en bloc excision.38
We report an uncommon case of GOC of the mandible. The lesion was initially misdiagnosed as BOC from the incisional biopsy due to the limited tissue availability. Our case highlights the diagnostic difficulties
and key features in distinguishing GOC from selected odontogenic cysts and MEC.
We would like to acknowledge all the staff members of oral medicine and radiology department for their support and guidance.
1.Dr.Pornpop Rattana-arpha, Lecturer, Department of Oral Diagnosis, Faculty of Dentistry, Khon Kaen University, Amphue Muang, Khon Kaen, Thailand, 2.Dr.Ploi Yongvanijchit, Oral and maxillofacial Surgeon, Dental Department, Nongkhai Hospital, 1158 Moo. 3, Meechai Road, Nai Muang, Muang, Nongkhai, Thailand, 3.Dr.Ekarat Phattarataratip, Lecturer, Department of Oral Pathology, Faculty of Dentistry, Chulalongkorn University, Henri-Dunant Road, Pathumwan, Bangkok-10330.
Lecturer, Department of Oral Pathology,
Faculty of Dentistry,
Henri-Dunant Road, Pathumwan,
Source of Support: Nil, Conflict of Interest: None Declared.
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