The reliability of MAML2 gene rearrangement in discriminating between histologically similar glandular odontogenic cysts and intraosseous mucoepidermoid carcinomas

Rare Histologic Imitator Central Mucoepidermoid Carcinoma Arising from Glandular Odontogenic Cyst of the Mandible: Case Report with Updated Review of Literature

Central mucoepidermoid carcinoma is a relatively rare salivary gland tumour of the jawbone. Glandular odontogenic cyst is another unique odontogenic developmental cyst characterised by glandular differentiation. Both entities share several histological characteristics, and a pre-existing Glandular odontogenic cyst can evolve into Central mucoepidermoid carcinoma. Case 1: A 56-year-old male presented with chief complaint of swelling in lower left facial region since 1 year. Histopathology revealed multicystic compartments resembling mucoepidermoid carcinoma, but strong positive expression of Cytokeratin 13 upon immunohistochemistry helped us in rendering the final diagnosis as Glandular odontogenic cyst Case 2: A 34-year-old female presented with a lesion on right side of face. Histologically, the biopsy specimen revealed both typical findings of a Glandular odontogenic cyst component and a recognizable component of Mucoepidermoid carcinoma. The results from cytokeratin profiling demonstrated that, while both Mucoepidermoid carcinoma and Glandular odontogenic cyst expressed Cyokeratins 7, 18, and 19. Cytokeratin 13 was interestingly exclusively expressed in Glandular odontogenic cyst. Present case findings showed that central mucoepidermoid carcinoma and Glandular odontogenic cyst may be part of the same disease spectrum. However, because the expression profile of Cytokeratin13 in mucoepidermoid carcinoma and Glandular odontogenic cyst was so diverse, it can be used to differentiate both.

Glandular Odontogenic Cyst: a Case Report and Literature Review

Background

The glandular odontogenic cyst is now a well-known entity comprising < 0.5% of all odontogenic cysts with a recent review tabulating about 200 cases in the English literature. Glandular odontogenic cyst shows epithelial features that simulate salivary gland or glandular differentiation. The importance of glandular odontogenic cyst relates to the fact that it has a high recurrence rate and shares overlapping histologic features with central mucoepidermoid carcinoma. The purpose of this paper is to describe the clinical, radiological, and histopathological features of a case of glandular odontogenic cyst with the course of treatment and 9-years follow-up, followed by a review of the literature.

Methods

A 63-year-old male was referred for further investigation of a mandibular radiolucency observed by his general dental practitioner. The main complaint was a murmuring sensation in the lower jaw right side. Radiological examination revealed a well-defined, unilocular, radiolucent lesion, involving the right mandible with 17 and 68 mm in mediolaterally and anteroposterior dimension, respectively.

Results

A total enucleation of the cystic lesion and surgical extraction of tooth #46, #47 and #48, was performed under local anaesthesia. Histopathologic examination revealed a glandular odontogenic cyst.

Conclusions

Glandular odontogenic cyst shows no pathognomonic clinico-radiographic characteristics, and therefore in many cases it resembles a wide spectrum of lesions. Diagnosis can be extremely difficult due to histopathological similarities with dentigerous cyst, lateral periodontal cyst and central mucoepidermoid carcinoma. Therefore a careful histopathological examination and a long-term follow-up (preferably seven years) are required to rule out recurrences.

Diagnostic Reliability of CRTC1/3::MAML2 Gene Fusion Transcripts in Discriminating Histologically Similar Intraosseous Mucoepidermoid Carcinoma from Glandular Odontogenic Cyst: A Systematic Review and Meta-analysis

BACKGROUND

Intraosseous mucoepidermoid carcinoma (IMEC) and Glandular odontogenic cyst (GOC) are those two pathological entities causing diagnostic dilemma due to the histopathological similarity. An accurate distinction between the two entities is difficult as both presents with a common radiological and histological similarities. The aim of our systematic review was to establish the diagnostic reliability of CRTC1/3::MAML2 gene fusion for the distinction between IMEC and GOC.

METHODS

A complete electronic literature search was made in MEDLINE by PubMed, Google Scholar, and EMBASE databases. Articles with keywords using molecular genetic findings of CRTC1/3::MAML2 gene fusion transcripts, IMEC and GOC were assessed and included for the systematic review.

RESULTS

Twelve subgroups having both qualitative and quantitative analysis revealed CRTC1/3::MAML2 sensitivity of 100% and specificity of 70.59% in differentiating GOC and IMEC. Fixed-effects model confirmed translocation-negative cases to have a decreased risk of association with IMEC (combined odds ratio 8.770, 95% confidence interval - 2.45 to 31.45, p < 0.002).

CONCLUSIONS

The current evidence supports that in all cases with positive gene fusion transcript of the CRTC1/3::MAML2 was specific for IMEC and was significantly differentiating it from GOC. Whereas cases of IMEC with negative gene fusion transcript pose diagnostic difficulty in differentiating from a GOC which is negative for CRTC1/3::MAML2 expression.

MAML2-Rearranged Primary Central Mucoepidermoid Carcinoma of the Mandible as an Incidental Finding: A Case Report and Review of the Literature of Molecularly Confirmed Cases

This report presents an extremely rare case of MAML2-rearranged primary central mucoepidermoid carcinoma (MEC) of the mandible that was discovered as an incidental finding. Our review of the literature identified 36 cases of MAML2-rearranged intraosseous lesions of the jaw (30 central MECs, 5 odontogenic cysts with mucous prosoplasia, and 1 glandular odontogenic cyst). Given the therapeutic indications for a diagnosis of MEC (a malignant neoplasm), MAML2 rearrangement should be confirmed in suspected cases of central MEC.

Unicystic Mucoepidermoid Carcinoma: A Pitfall for Clinical and Pathologic Diagnosis

Unicystic mucoepidermoid carcinoma (UC-MEC) is a rare MEC variant, and its diagnosis is frequently problematic. This study is aimed at summarizing its clinicopathologic characteristics, treatment, and prognosis and proposing key points to avoid missed diagnosis and misdiagnosis in clinical and pathological conditions. This retrospective study included 30 UC-MEC cases, and the clinical findings were collected from the clinical medical records. Radiographic features, histologic behaviors, MAML2 rearrangement by fluorescence in situ hybridization (FISH), and follow-up data were analyzed. Moreover, glandular odontogenic cyst (GOC) and cytadenoma (CA) were used as controls. In the UC-MEC group, 19 patients were female (63%), and 11 were male (37%). The mean patient age was 39.5 (range, 7–72 years). The affected locations included the jaw (8 maxillary, 3 mandibular) and salivary glands (7 parotid, 11 palates, and 1 floor of the mouth). The chief complaint was swelling; the lesions were all cystic, among which 66.7% were well circumscribed and 33.3% poorly defined. Microscopic examination showed two UC-MEC histologic subtypes. Type A presented as a single cyst with mural thickening (8/30, 27%) lined predominantly by epidermoid cells with interspersed intermediate and mucinous cells, and type B (22/30, 73%) showed infiltrative tumor islands in the cystic wall or the surrounding tissue. FISH analysis suggested that approximately 66.7% of UC-MEC harbored a MAML2 rearrangement. During the median follow-up period of 42 months (range, 6–120 months), all type A patients and 68% of type B patients who underwent complete surgical resection lived without relapse. Seven cases with type B cancer that underwent curettage initially had local recurrence. Clinicians and pathologists hardly recognize UC-MEC owing to its cystic architecture. Specific epidermoid, mucous, and intermediate tumor cells, and MAML2 fusion testing, are essential to avoid potential diagnostic pitfalls. Prompting and completing resection surgery with negative margins would have a favorable prognosis.

Clinical and radiologic spectrum of glandular odontogenic cysts: A multicenter study of 92 cases

OBJECTIVE

The purpose of this multicenter retrospective study was to report the clinical and radiologic features of 92 glandular odontogenic cysts (GOCs) diagnosed over a 20-year period.

STUDY DESIGN

Histologically confirmed cases of GOC were retrospectively reviewed from 4 oral pathology laboratories in South Africa and Brazil to categorize the clinical and radiologic spectrum of GOCs.

RESULTS

The mean age of patients was 46 years (range 17-87) with a male-to-female ratio of 1.2:1. GOCs had a mandibular predilection (68%), with 42% of all cases located anteriorly. Additionally, 42% of cases crossed the midline. Radiologically, most lesions were unilocular (53%) and uniformly radiolucent (97%), with well-demarcated borders (93%). Cortical expansion (62%), loss of cortical integrity (71%), and maxillary sinus (67%) and nasal cavity encroachment (72%) were common findings. Significant differences in lesions between the 2 countries were discovered in sex predilection, clinical signs and symptoms, and lesion locations within the mandible and maxilla.

CONCLUSION

GOCs present with a wide spectrum of clinical and radiologic features, ranging from cysts with typical GOC-like presentations to more aggressive lesions. The need for advanced imaging in the surgical planning of GOCs exhibiting radiologic signs of aggression is justified based on the high recurrence rate.

miR-22 and miR-205 Drive Tumor Aggressiveness of Mucoepidermoid Carcinomas of Salivary Glands

Objectives

To integrate mRNA and miRNA expression profiles of mucoepidermoid carcinomas (MECs) and normal salivary gland (NSGs) tissue samples and identify potential drivers.

Material and Methods

Gene and miRNA expression arrays were performed in 35 MECs and six NSGs.

Results

We found 46 differentially expressed (DE) miRNAs and 3,162 DE mRNAs. Supervised hierarchical clustering analysis of the DE transcripts revealed two clusters in both miRNA and mRNA profiles, which distinguished MEC from NSG samples. The integrative miRNA-mRNA analysis revealed a network comprising 696 negatively correlated interactions (44 miRNAs and 444 mRNAs) involving cell signaling, cell cycle, and cancer-related pathways. Increased expression levels of miR-205-5p and miR-224-5p and decreased expression levels of miR-139-3p, miR-145-3p, miR-148a-3p, miR-186-5p, miR-338-3p, miR-363-3p, and miR-4324 were significantly related to worse overall survival in MEC patients. Two overexpressed miRNAs in MEC (miR-22 and miR-205) were selected for inhibition by the CRISPR-Cas9 method. Cell viability, migration, and invasion assays were performed using an intermediate grade MEC cell line. Knockout of miR-205 reduced cell viability and enhanced ZEB2 expression, while miR-22 knockout reduced cell migration and invasion and enhanced ESR1 expression. Our results indicate a distinct transcriptomic profile of MEC compared to NSG, and the integrative analysis highlighted miRNA-mRNA interactions involving cancer-related pathways, including PTEN and PI3K/AKT.

Conclusion

The in vitro functional studies revealed that miR-22 and miR-205 deficiencies reduced the viability, migration, and invasion of the MEC cells suggesting they are potential oncogenic drivers in MEC.

Central mucoepidermoid carcinoma arising directly from a glandular odontogenic cyst of the mandible: a case report

BACKGROUND

Central mucoepidermoid carcinoma (MEC) is a rare salivary gland tumor that affects the jawbone. Glandular odontogenic cyst (GOC) is also a rare odontogenic developmental cyst with glandular differentiation. GOC shares some histological features with central MEC, and a pre-existing GOC can develop into central MEC. Here, we present a rare case of central MEC developed directly from a pre-existing GOC of the mandible.

CASE PRESENTATION

A 67-year-old Japanese man presented with a cystic lesion in the right third molar region. Histologically, the biopsy specimen demonstrated both typical findings of a GOC component lined with non-keratinized squamous epithelium and a recognizable component of central MEC consisting of polycystic nests with mucous cells, intermediate cells, and epidermoid cells in the cyst wall. The results from the immunohistochemistry for cytokeratin (CK) profiling demonstrated that, while both central MEC and GOC expressed CKs 7, 14, 18, and 19, CK13 was interestingly exclusively expressed in GOC. Fluorescence in-situ hybridization (FISH) revealed the rearrangement of the Mastermind like (MAML)-2 gene in both the MEC and GOC components.

CONCLUSIONS

Our case suggests that central MEC and GOC may be in the same spectrum of diseases caused by the rearrangement of the MAML-2 gene. However, given that the expression profile of CK13 was completely different between central MEC and GOC, they can be considered as separate tumors. Overall, we demonstrated a rare case in which central MEC may have originated directly from the GOC.

Unique case of glandular odontogenic cyst showing mucoepidermoid carcinoma-like islands in cystic wall

Glandular odontogenic cyst (GOC) is a very rare jaw cyst accounting for 0.2% of all odontogenic cysts. It presents usually in adults with a slight male predominance. It shows radiological, histopathological and even immunohistochemical overlap with low grade intraosseous mucoepidermoid carcinoma (MEC) but their distinction is crucial. A 57-year-old woman with bilocular radiolucency in the anterior mandible crossing the midline is described here. Microscopy features were consistent with glandular odontogenic cyst but multiple MEC-like islands were seen in the capsule, creating a diagnostic head trip with low grade intraosseous MEC. However, the absence of cellular atypia and epidermoid and intermediate cells led to a final diagnosis of GOC, with close follow-up of the patient recommended. This rare finding shows the relation between GOC and MEC or the origin of MEC from GOC.

Glandular Odontogenic Cyst-A Case Series

The glandular odontogenic cyst (GOC) is an uncommon jawbone cyst with a challenging diagnosis because of the presence of several clinical and histopathologic overlaps with other odontogenic lesions and central mucoepidermoid carcinoma. To date, less than 200 cases of GOC have been published in the literature with reliable clinical and histopathologic information. Furthermore, the lack of a well-documented GOC case series impairs a more detailed understanding about the biological behavior and appropriate management of the lesion. Therefore, in this study, we report 3 well-documented cases of GOC in the literature. In one of the cases, the incisional biopsy was misdiagnosed as a dentigerous cyst, and the lesion recurred. Therefore, we also discuss key points regarding the diagnosis and treatment of GOC.

Gardner's Cyst Enswathing the Maxillary Antrum: Report of A Rare Case and Review of Literature

Glandular odontogenic cyst (GOC) was named so by Gardner and the credit of discovery can be attributed to the work of Padayachee and Van Wyk (1987). The incidence of GOC is said to be between 0.012% and 1.3%. Even so, a little over 100 cases are reported in English literature. Mandible is more commonly affected than maxilla (20%) with almost 80% cases reported, with an anterior predilection. Even though GOC affecting maxilla is discussed in the literature, to the best of our ability, we could find that, in India, less than five cases affecting the maxillary sinus is ever reported, with none explaining about such a huge cyst that has encompassed the whole of the ipsilateral maxillary sinus. The aim to publish this case report was to understand the rarity in pathology, which GOC encompasses. Such rare cases if reported need to be published for the knowledge, prompt diagnosis, and appropriate treatment planning. Any pathology in the head and neck region should be seen with an eagle’s eye for appropriate management to increase patients’ quality of life.