Immunohistochemical expression of matrix metalloproteinases 1, 2, and 9 in odontogenic myxoma and dental germ papilla

Odontogenic myxoma: A causality dilemma - Report of a nonpareil case and review of literature

Odontogenic myxoma is a benign locally aggressive neoplasm with a sparse prevalence and incertitude histogenesis. They constitute 3%-6% of odontogenic tumors in gnathic bones. It is ubiquitously seen between vicenarian to early quadragenarian group with female proclivity and fondness to the mandibular jaws. They are silent lesions clinically and show myxoid stroma amidst fibrous background. This report highlights central odontogenic myxoma in a 43-year-old male patient and focuses on concepts, differential diagnosis, molecular concepts and treatment aspect.

Kallikrein 4 and matrix metalloproteinase-20 immunoexpression in malignant, benign and infiltrative odontogenic tumors

CONTEXT

Matrix metalloproteinase-20 (MMP20) (enamelysin) and kallikrein 4 (KLK4) are enzymes secreted by ameloblasts that play an important role in enamel matrix degradation during amelogenesis. However, studies have shown that neoplastic cells can produce such enzymes, which may affect the tumor infiltrative and metastatic behaviors.

AIMS

The aim of this study is to assess the biological role of MMP20 and KLK4 in odontogenic tumors.

MATERIALS AND METHODS

The enzymes were analyzed immunohistochemically in ameloblastoma, adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor, keratocystic odontogenic tumor with or without recurrence and odontogenic carcinoma.

STATISTICAL ANALYSIS USED

Clinicopathological parameters were statistically correlated with protein expression using the Fisher's exact test. Kruskal-Wallis and Wilcoxon-independent methods were used to evaluate the differences in median values.

RESULTS

Positive Immunoexpression was detected in all benign lesions, with a prevalence of 75-100% immunolabeled cells. Patients were predominantly young, Caucasian, female, with slow-growing tumors located in the mandible causing asymptomatic swelling. No KLK4 expression was seen in carcinomas, and the amount of MMP20-positive cells varied between 20% and 80%. Rapid evolution, recurrence and age >60 years characterized the malignant nature of these lesions.

CONCLUSIONS

Data showed that KLK4 and MMP20 enzymes may not be crucial to tumoral infiltrative capacity, especially in malignant tumors, considering the diversity and peculiarity of these lesions. The significant immunoexpression in benign lesions, remarkably in AOT, is likely associated with differentiated tumor cells that can produce and degrade enamel matrix-like substances. This would be expected since the histogenesis of odontogenic tumors commonly comes from epithelium that recently performed a secretory activity in tooth formation.

Assessment of CD-105 as an Angiogenic Modulator in Odontogenic Myxomas and Dental Follicles

Aim Odontogenic myxoma is a benign intraosseous neoplasm of the jaws, with a locally aggressive behavior and a high recurrence rate. CD-105 is a homodimeric cell membrane glycoprotein and is a component of the TGF-β1 growth factor receptor complex that modulates angiogenesis by regulating the proliferation, differentiation and cellular migration. The aim of this study is to quantify the microvascular density of the odontogenic myxoma based on the expression of CD-105. Materials and Methods The analysis included 18 odontogenic myxoma and 18 dental follicles as controls. A standard immunohistochemical procedure was performed with the CD-105 antibody. Five representative fields (40×) of the odontogenic myxoma and the dental follicles were selected to determine the microvascular density, which was then followed by a descriptive and comparative statistical analysis. Results Dental follicles presented a significantly higher microvascular density compared with odontogenic myxoma (P = .001). The odontogenic myxoma smaller than 3 cm showed a greater microvascular density than those larger than 3 cm in size (P > .05), and the microvascular density was lower in large odontogenic myxomas as compared with the dental follicles (P = .003). Conclusion A weaker expression of CD-105 in odontogenic myxoma might indicate a lower angiogenic activity, suggesting that vascular proliferation has a limited role in the growth mechanisms and in the aggressive behavior of this neoplasm.

Odontogenic Myxoma: a study based on biopsy material over a 40-year period

AIM

Odontogenic tumors, including odontogenic myxomas (OMs) are regarded as rare neoplasms in the human body. Nevertheless, they may be problematic for diagnosis and treatment planning due to possible variations between different races and countries. The aim of the current study was to present the clinicopathologic features of OM in an Iranian population over a 40-year period and compare them with those reported elsewhere.

MATERIALS AND METHODS

Clinical/demographic data and histologic slides of OMs and all lesions that could be considered in their differential diagnosis, reported from 1967-2008 were analyzed. Statistical analysis was performed using χ(2) and t-test and p < 0.05 was regarded significant.

RESULTS

Forty OMs were identified, of which 42.5% occurred in men (mean age, 27.4 years) and 57.5% in women (mean age, 28.2 years). Most tumors were observed in the posterior mandible. All cases possessed the classic World Health Organization histologic features; while 3, 15 and 6 cases showed epithelial rests, residual bone and conspicuous collagen bundles, respectively. Five patients were followed and none of their tumors recurred.

CONCLUSION

The clinicopathologic characteristics of the current Iranian population are similar to most other reports with a predilection for the posterior mandible, 3rd decade and female subjects; however, there were variations in microscopic features of the studied cases. Clinical significance: Clinical and histologic information on OM in different populations may be useful in clinical settings and treatment planning. Reporting more detailed histologic data can help clarify the biology of this tumor and aid in its histopathologic diagnosis. i

Expression of MMP-2 and MMP-9 in odontogenic myxoma in a child: report of a clinical case

BACKGROUND

Odontogenic myxoma (OM) is a benign, locally invasive, non-metastasizing neoplasm of the jaw bones. Despite the benign nature of these lesions, there is a high rate of recurrence and the current recommended therapy, depending on the size and behaviour of the lesion, can vary from curettage with peripheral ostectomy, segmental resection up to radical resections for more aggressive lesions. OM is a rare tumour which occurs predominantly in the third decade of life and it is rare in children. Matrix metalloproteinases (MMPs) are a family of extracellular endopeptidases responsible for the degradation and remodelling of extracellular matrix, they are known to be involved in the progression and invasiveness of many types of tumour. MMPs have been studied in OM because of their well-known role in extracellular matrix degradation, tumour invasion and recurrence.

CLINICAL CASE REPORT

We report a case of OM in a 6-year-old boy. A conservative excision was accomplished. The mass was excised without affecting the mandibular bone and the inferior alveolar nerve. Curettage and removal of the first right inferior molar were performed. After 6-month follow-up, no evidence of recurrence was found.

EXPERIMENTAL DATA

We investigated the expression of MMP-2 and MMP-9 in this case of OM in a child. RT-PCR showed the expression of both MMP-2 and MMP-9 mRNAs. Immunohistochemistry showed a weak MMP-2 protein expression while MMP-9 protein was not detected.

CONCLUSION

In this case of OM in a child, we report lack of recurrence after excision associated with low MMP-2 protein expression and absence of MMP-9. We believe it is worthy to deeply investigate the relationship between MMPs expression and OM behaviour with the aim to use MMPs as prognostic and/or therapeutic markers in OM.

Surgical treatment of odontogenic myxoma

BACKGROUND

There is no consensus about the surgical treatment of odontogenic myxoma. The aim of the current study was to present our experience and discuss the surgical management and outcome in 10 patients diagnosed with odontogenic myxoma.

METHODS

A retrospective review of charts of patients who were surgically treated for odontogenic myxoma was performed. Patients were recalled, and eventual recurrences were investigated.

RESULTS

Eight lesions were mandibular, whereas 2 were maxillary. In 3 patients, enucleation and curettage was performed. Instead, in the remaining 7 patients, segmental resection and immediate reconstruction were decided. At follow-up, no patient showed recurrence of the lesion.

CONCLUSIONS

Our protocol is to perform conservative surgery by enucleation and curettage when lesions were smaller than 3 cm, whereas a segmental resection with immediate reconstruction is preferred in patients affected by bigger tumors. Long-term follow-up is required, in particular when conservative surgery is preferred.