Odontogenic myxoma is a rare, benign mesenchymal intraosseous neoplasm which is nonencapsulated and is called ‘locally malignant’ on account of its exceptionally high local aggressiveness and nonmetastasizing nature 1.
Although soft tissue myxomas are frequently found, their intraosseous counterparts are rarely found, and those that are encountered are almost exclusively confined to the jaws.
A few reports of their occurrence in the clavicle, ribs, femur, and petrous bone of skull have been reported, most of the investigators have found otherwise. Of all the biopsies submitted, odontogenic tumors comprise not more than 1.3%, and, of all the odontogenic tumors and odontogenic myxoma contributes to only 3–11% 2,3.
Odontogenic myxoma most frequently occurs in second or third decade of life; the tumor shows a slight female predilection and mandible is more commonly involved than the maxilla. Clinically, it is a slow growing, expansile, and painless tumor which may cause root resorption, tooth mobility, bone expansion, cortical destruction, and facial distortion 1,2,4. Radiographically, the classic presentation is that of a multilocular radiolucency with well-developed locules consisting of fine trabeculae arranged at right angles, known as tennis racquet or step ladder pattern 1. On macroscopical examination, the surgical specimen is characteristically loose, slippery or gelatinous in nature. Histopathologically, the lesion consists of loosely arranged spindle, stellate-shaped or round cells, in an abundant myxoid stroma 5. Conservative treatment is usually associated with recurrence. So a radical excision and a close follow-up are advocated by most surgeons 4,5.
The purpose of this article is to report a case of odontogenic myxoma in a 26-year-old female arising in the tooth bearing portion of the lower jaw, and extending to involve the entire half of the mandible including the ramus, resulting in a gross facial deformity within a span of 1.5 years. The lesion revealed the classic clinical, radiographical, and histopathological characteristics of a myxoma. The approval of the patient has been taken verbally.
A female patient aged 26 years presented with the chief complaint of swelling in the lower left side of her face (Fig. 1). History revealed that the swelling had gradually increased in size since its onset within a span of 1.5 years. The swelling was not associated with pain, any discharge or paresthesia. Her family and medical history were not contributory. The patient initially noticed a small swelling in the lower left vestibule which slowly grew to the present size.
Extraoral examination revealed a single diffuse painless swelling which is nontender and bony hard at the left body region of the mandible, of ∼3–4 cm in size (Fig. 2). There is no local rise in temperature or change in color of the overlying skin. No lymphadenopathy was observed. Intraoral examination revealed a single well defined localized swelling at left buccal vestibular region, extending from left lower premolar to second molar. Thirty-five and 36 were displaced. Mobility of 34, 35, 36, and 37 was observed. No erythema, ulceration or pus discharge in the overlying mucosa was evident (Fig. 3).
Radiograph orthopantogram showed a multilocular radiolucency extending from the midline to left ramus region, with fine trabeculae intersecting at right angles, was prominent thus creating a classical step ladder appearance. Root resorption of 35, 36, 37, and 38 were prominent (Fig. 4).
Incisional biopsy was carried out under local anesthesia after all necessary investigations were completed. On macroscopic examination the incisional biopsy specimen was in multiple pieces, 1–2 cm in size, whitish in color, transparent and slippery in nature, and soft in consistency. On microscopic examination hematoxylin and eosin stained section revealed loosely arranged stellate-shaped cells with intermingled fibrillar processes in a homogenous mucoid ground substance with few collagen fibrils and capillaries (Fig. 5). Very few scattered odontogenic epithelial rests, areas of hemorrhage, and foci of bony trabeculae were visible leading to the histopathological diagnosis of odontogenic myxoma (Fig. 6).
Based on the incisional biopsy report, progressive nature of the lesion, and cortical expansion, radical resection with hemimandibulectomy was advised. But unfortunately the patient did not turn up for surgery and was lost for follow-up.
Odontogenic myxoma is a nonencapsulated benign tumor of the jaw bones, comprising around 3–6% of all odontogenic tumors. Previous studies by White and colleagues 6 refer the tip of the incidence with an age range of 11–70 years, but the majority of the cases are between 10 and 40 years of age 7. Zimmerman and Dahlin 8 reported that the average age of occurrence for the odontogenic myxoma is 26.5 years. Majority of the investigators reported that there is a slight female preponderance, mandible is more commonly involved than the maxilla, and the lesion has a silent locally destructive nature 1,3,5,8,9.
Odontogenic myxoma often grows without symptoms, most commonly presenting as a painless swelling. Pain, displacement of teeth, and paresthesia are uncommon, thus the lesion can reach a considerable size before the patients becomes aware of its presence to seek treatment 10.
The classical radiographic features of the odontogenic myxoma, where the bony trabeculae of a multilocular radiolucency intersect at right angles and create a step ladder pattern, the lesion causes cortical expansion and thinning, tooth mobility, and root resorption 1,4,8, were readily identifiable in the orthopantogram of the patient.
The cause and histogenesis of the tumor remain controversial, but the tissue of origin is considered mesenchymal and two theories of origin have been proposed. Firstly, the tumor results from myxomatous degeneration of fibrous stroma. Secondly, it is derived from the mesenchymal portion of the tooth germ, that is, the dental papilla, follicle or periodontal ligament.
On the basis of its common site of occurrence (tooth bearing areas of jaws), usual age of occurrence (second or third decades), the striking histological resemblance to dental mesenchyme, and the sporadic presence of odontogenic epithelial islands, the WHO and many authorities consider this neoplasm to be of odontogenic mesenchymal origin 11.
The aggressive nature of odontogenic myxoma is well documented in the literature. The tumor is not radiosensitive and treatment of choice is surgery. Despite surgery been established as the treatment of choice of these tumors, no unanimous consensus exists concerning the extension of surgery. Although it is our opinion that enucleation should be avoided, curettage with scarification of the cavity with acrylic bur may be used for small mandibular lesions particularly in the anterior region and especially where the patient is educated and available for periodic reviews. It would appear that for extensive lesions a more radical approach is more appropriate.
Odontogenic myxoma is a slow growing benign, locally malignant tumor, notorious for recurrence. Due to the unspecific nature of these lesions along with diagnostic and operative dilemmas related to myxomatous tumors, a sound knowledge with proper histopathological diagnosis is required for maxillofacial surgeons to improve skills in their management.
Conflicts of interest
There are no conflicts of interest.
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