Odontogenic myxoma: a clinicopathological study in a South African population

Abstract

BACKGROUND: Odontogenic myxoma is a benign, locally aggressive neoplasm of the jaws. Prevalence rates range between 0.5% and 17.7% of odontogenic tumours. There are few reports in the literature on this lesion in African populations, and therefore, this study aimed to report on odontogenic myxoma in a South African population over a 40-year period. METHODS: The clinical records and orthopantomograms of 29 histopathologically diagnosed odontogenic myxoma were retrospectively analysed. Details of age, gender, ethnic origin and clinical, histological as well as radiological features were recorded. RESULTS: The ages of patients ranged from 7 to 44 years with a mean of 21.3 years. The male-to-female ratio was 1:2.6 with the majority of patients being of mixed race and Africans. Clinically, 31% complained of pain while 58.6% had a history of swelling. The majority of odongenic myxomas (62.1%) were located in the mandible with the posterior region being most commonly affected. Multilocular lesions (69.2%) were more common and were significantly larger than unilocular lesions (P < 0.05). The outline of these tumours was mostly well-defined (84.6%) with different degrees of cortication. Only one tumour caused tooth resorption, while 20 cases (76.9%) caused tooth displacement. Six tumours expanded into the maxillary sinus, and 14 tumours caused expansion of the mandible. CONCLUSIONS: Odontogenic myxomas have variable clinical, radiological and histological features. Most of these features in this population were similar to other populations. It is mandatory to use conventional radiographs along with histopathological examination to aid in arriving at an accurate diagnosis.

Characteristic features of the odontogenic myxoma on cone beam computed tomography

“…Radiologically, these residual bony trabeculae and dense fibrous tissue manifested as septa in multilocular OMs. 8 As reported previously, fine and straight septa separated the lesion into triangular, square or rectangular compartments, which are described as "honeycomb" or "tennis racket". 3,6,8,11 These features significantly aided in the proper diagnosis of OM.…”

“…8 As reported previously, fine and straight septa separated the lesion into triangular, square or rectangular compartments, which are described as "honeycomb" or "tennis racket". 3,6,8,11 These features significantly aided in the proper diagnosis of OM. In this present study, only 10 multilocular OMs showed that typical appearance, and the remaining 5 demonstrated fewer septa.…”

“…The findings above correspond to previous studies on OMs. 3,6,8 Histologically, the trabeculae of woven bone were seen dispersing in 25.8-56% lesions. Radiologically, these residual bony trabeculae and dense fibrous tissue manifested as septa in multilocular OMs.…”

“…Most lesions of OM are separated by straight septa forming square, rectangular or triangular spaces and show a "honeycomb", "soap bubble" or "tennis racquet" appearance. 3,6,8,11 However, plain radiography is not reliable enough to demonstrate the extent and fine inner structures of the tumour. 3,12 Therefore, the use of advanced medical imaging including MRI, CT and CBCT are useful in the aid of establishing a proper diagnosis with the ability of clearly displaying a tumour in three-dimensional accuracy and perspective.…”

“…6,7 The premolar and the molar regions of the mandible are the sites of most common occurrence for OM. 3,6,8 Patients afflicted with an OM generally notice a painless, slowly enlarging expansion of the jaw with possible tooth loosening or displacement. 3,4,9 As the tumour expands, it frequently infiltrates adjacent structures.…”