Volume 2, Issue 3 , Pages 173-175, September 2007
Odontogenic myxoma: A report of an unusual pediatric case
Article Outline
Summary
Odontogenic myxoma (OM) is a rare tumor that mainly affects adolescents and adults. This tumor is extremely uncommon in children and exceptionally rare in infants. Generally it is a slow growing, benign mass, that occurs in the mandible. An unusual presentation of this tumor as a rapidly expanding lesion in the right maxilla of an infant is reported. The epidemiologic, clinicoradiologic and pathologic features of the myxoma are discussed and similar published cases are reviewed. Two peculiarities are highlighted in this case: first the very young age of this patient, second the rapidly growing aspect.
Keywords: Odontogenic tumors, Myxoma, Infant, Pathology, Surgery
1. Introduction
Myxoma is a relatively rare benign tumor found mainly in the left atrium of the heart or centrally in bone. In bone sites it is exclusively found in the jaw. It represents 3–6% of all odontogenic tumors and occurs more often between the ages of 10 and 40 years [1]. It is more common in females and preferentially located in the mandible [2]. In this case, an unusual presentation of a rapidly expanding odontogenic myxoma in the maxilla was identified in an infant. The diagnosis was established only histologically. The epidemiologic, clinicoradiologic and pathologic features of the odontogenic myxoma are discussed with review of the available literature.
2. Case report
A 10-month-old boy presented with a 1-month history of jaw swelling associated with a palpebral edema. The head and neck examination showed a 5
cm painless cystic mass of the right hemiface with swollen nasolabial cleft. The skin overlying the area was intact. He did not have any adenopathy or neurological defect. The rhinologic examination showed a left deviation of the nasal septum. Computed tomography scan revealed a 5cm smooth unilocular mass that invaded the right maxilla (Fig. 1). Surgery was planned to remove the mass. A right lateral rhinotomy was carried out. The tumor was soft, extending from the right palate, including the teeth, to the floor of the orbit. The latter was invaded. The zygomatic arc was eroded. Laterally, it caused a displacement of the sinonasal wall and extended into the maxillary sinus causing a total defect of the anterior wall. The patient received a conservative treatment, consisting of total enucleation and curettage. The specimen consisted of a 6cm×3.5cm×5cm grey white mass, gelatinous in consistency, with an attached sclerosing membrane. This membrane was 5.5cm long. The cut surface was multicystic and translucent (Fig. 2). A microscopic examination of hematoxylin–eosin stained sections showed a proliferation of loose cellular tissue containing spindle, round or pyramidal cells. These cells had eosinophilic cytoplasm, round bland nuclei with or without a nucleolus and were surrounded by a very loose, pale basophilic myxoid stroma (Fig. 3). Coarse bands of fibrous and vascular tissue were present focally between the tumor cells. No epithelial elements were identified. The sclerosing membrane was composed of the same tumoral tissue confined by a thin rim of bone. The diagnosis was odontogenic myxoma. The patient did not return after treatment.
Fig. 1.
CT scan: large smooth soft tissue unilocular paranasal mass causing destruction of the right maxilla.
Fig. 2.
Gross specimen: cut surface depicting the myxoid multicystic grey white appearance of the mass, with attached sclerosing membrane.
Fig. 3.
Medium-power view showing hypocellular tumor with prominent myxoid stroma (hematoxylin and eosin, original magnification 100×).
3. Discussion
Odontogenic tumors and particularly the myxoma are relatively uncommon lesions in children. The majority of patients with an odontogenic myxoma were between the second and fourth decades of life [2], [3], [4]. In a review of 367 cases, 8.4% occurred in children aged 4–16 years [5]. In the present case, the tumor occurred in an infant aged 10 months. To the best of our knowledge, only four similar cases were reported in children under the age of 18 months [1]. Several studies have reported that sex predilection favors females [1], [2], [6], [7]. However, others have not observed any gender predilection [4]. Most authors consider the mandible as the site of predilection of the tumor over the maxilla [1], [3], [8], [9]. Myxoma is a benign tumor but it is locally aggressive causing bone perforation with subsequent invasion into the soft tissues [2], [3], [4]. It can be mistaken for a non-neoplastic lesion; which first happened in the present case. It is usually characterized by a slow painless growing tumor, can cause tooth displacement and mobility, facial asymmetry, delayed eruption of teeth, disturbance of speech and mastication, pain and paraesthesia and oral mucosal ulceration [2], [8]. In the present case the tumor appeared to grow rapidly without any other symptoms. Radiographically, myxomas frequently appear as unilocular or multilocular radiolucencies separated by straight or curved bony septa, or as a mixture of radiolucency and radio-opacity. Computed tomography depicts a multilocular soft tissue mass with bone destruction and thinning [1], [2], [8], [10]. Some potential difficulties exist when trying to reach a proper diagnosis. Lesions that should be included in the differential diagnosis are ameloblastoma, hemangioma, aneurismal bone cyst, and simple cyst [2], [4]. Macroscopically, typical cases show an unencapsulated mass, but with well-defined borders. The cut surface is soft, grey white and gelatinous [1], [2], [4]. Histologically, it is a hypocellular tumor composed of loosely arranged, spindle shaped and stellate cells in a background of abundant myxoid stroma. The cells have round-to-oval bland nuclei with finely stippled chromatin [4]. Atypical nuclei are often encountered, but cellular polymorphism, prominent nucleoli and atypical mitotic figures are not seen [2]. The cytoplasm is eosinophilic. Small islands or strands of odontogenic epithelium are rarely observed [3]. As in the present case, most myxomas have some collagen with tiny capillaries. A panel of immunohistochemical stains showed consistent positive staining with vimentine. Desmin, smooth muscle actin, S100, and cytokeratin stains are either negative or equivocal and focally positive [2], [4]. Odontogenic myxoma is thought to occur as a result of disturbances in the development of teeth and associated structures, so the origin is believed to be the mesenchyme of the developing tooth or the periodontal ligament [2], [11]. Despite the fact that odontogenic myxoma shows aggressive local growth, it is believed that it never undergoes malignant transformation or gives rise to metastasis [2]. The recommended treatment modality is either radical resection or conservative tumor excision depending on tumor size [2], [8]. Radical surgery including a margin of 1.5–2cm seems to be the best option to prevent recurrences as much as possible [2]. Recurrence rates average about 25% and typically occur during the first 2 years after excision. It is the result of insidious local invasion into cancellous bone. So the patient should be closely observed for at least 5 years [9].
4. Conclusion
This case is particular by its unusual clinical presentation as a rapidly growing odontogenic myxoma in an infant. Oral clinicians, radiologists and pathologists should be aware of this misleading mode of presentation.
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PII: S1871-4048(07)00036-6
doi:10.1016/j.pedex.2007.05.003
© 2007 Elsevier Ireland Ltd. All rights reserved.
Volume 2, Issue 3 , Pages 173-175, September 2007
