This article reports a case of soft tissue myxoma located in the maxillary anterior region in a male patient, describing treatment and clinical follow-up. From the case report, conduction, differential diagnoses and treatments for the myxoma of soft tissue is presented.
Materials and methods
A 54-year-old male, caucasian, upperly edentulous patient reported an increase in volume in the left genic region, that had been evolving for ten years asymptomatically, after extraction of a tooth. Treatment included surgical excision and strict outpatient follow-up without any recurrence.
The extramuscular soft tissue myxoma in the maxillofacial region is a rare benign neoplasm, with low recurrence, slow and painless growth.
The definitive diagnosis can be performed only after histopathological analysis and the treatment of choice should be surgical excision with safety margin, in order to avoid recurrences, and a strict follow- up.
Maxilla, Maxillofacial, Myxoma, Odontogenic tumors, Soft tissue.
Myxoma is a tumor of the primitive mesenchyme, consisting of undifferentiated non metastatic star cells, arranged in a mucoid matrix. It is a rare, locally infiltrative benign tumor of the connective tissue, arising in bones and soft tissues, which has an asymptomatic and slow growth, but with a locally aggressive behavior (1). In the head and neck they are usually located in the gnathic bones with a higher prevalence in posterior mandibular region. Frequency varies from 3% to 20% among odontogenic tumors, it is the third most reported in studies, after odontoma and ameloblastoma (2). The soft tissue myxoma (STM) has a rarer frequency, and a slower and less aggressive growth than the intraosseous ones, as well as a lower recurrence. In the literature there are few reports of STM, similarly, no clinical data is found in standard books of pathology. In the facial region, it is usually found as an asymptomatic gingival mass without bone involvement (3).
This paper reports a case of soft tissue myxoma located in the anterior region of the maxilla of an adult male patient.
A 54-year-old male, caucasian, upperly edentulous patient, came to the observation seeking treatment for the increased volume in the right genic region, that had been evolving for ten years asymptomatically, after extraction of tooth 6 (Figure 1).
Clinically, it had normal mucosal appearance and color, with a soft consistency, located in the canine sulcus region, measuring approximately 50 x 30 mm (Figure 2).
A low-density image with cystic ovoid formation was observed on the tomography in the primary vestibular fascial space (Figure 3).
According to clinical and imaging examination, the diagnostic hypothesis was lipoma.
The treatment was surgical mass excision, with wide margins for resection, without rupture during excision. Macroscopically, the lesion presented a gelatinous and soft consistency, spherical appearance, and brown color (Figure 4); its dimensions were 52 x 42 x 32 mm.
The patient showed no changes in the immediate postoperative period, and was discharged with instructions and care, as well as pain-control medication and antibiotic therapy.
Histologic analysis showed arranged cells of stellate, fusiform or rounded shape. In the fundamental myxoid substance small islands of odontogenic epithelial remains could be found (Figure 5); these findings are compatible with myxoma.
The follow-up after three years, showed absence of changes, confirming the low potential of recurrence of this lesion.
The appearance of soft tissue myxoma is variably distributed in the body, being reported as more common in different places than the head and neck. Its growth is slow and variable, asymptomatic and may remain stable for several years (1).
Myxoma of the soft tissue is more rare and less invasive compared to intraosseus myxoma, occurring intra or extramuscularly. It presents a lower frequency than other odontogenic tumors (3), with a slight female preference. There's a greater consensus that myxomas are derived from primitive embryonic mesenchyme or fibroblasts that are supposed to produce an excess of mucopolysaccharides, being unable to form collagen (1). Despite this, the histogenesis remains indefinite, and future studies are necessary to define its real origin.
Usually, the diagnosis of odontogenic myxoma is made through conventional radiographic (CR) examination and histopathological confirmation. Alternative imaging exams, such as CT scans and magnetic resonance imaging (MRI), offer a reinforcement to the diagnosis of CR limitations. These demonstrate the extent of tumors in the different planes and determine their tissue density (4).
The treatment for soft tissue myxoma in the head and neck area includes the excision with adequate margins, in order to prevent recurrences. There's a conservative indication for lesions near to noble structures, especially in young patients (1). Follow-up should be of at least two years, as during this period recurrence is most likely to occur. Proper surgical excision defines a good prognosis of the lesion (5).
The differential diagnosis, for myeloid-like soft tissue lesions, includes myxoid liposarcoma, myxofibrosarcoma, extraosseous chondrosarcoma and synovial cyst (6).
Microscopy is mandatory for definitive diagnosis. Histologically, soft tissue myxoma is formed by fusiform or rounded star cells, in an abundant, myxoid stroma, containing few collagen fibrils (3).
The extramuscular soft tissue myxoma in the maxillofacial region is a rare benign neoplasm of mesenchymal origin with an infiltrative nature and low recurrence, slow and painless growth, the definitive diagnosis of which is performed after histopathological analysis. The treatment of choice should be the surgical excision with safety margin, in order to avoiding recurrence, and strict follow-up, even though there are no reports in the literature of cases of malignancy.
Source of support: This study needed no form of support.
Conflict of interest: The authors declare no conflict of interest
Ethic approval: This case does not contain any experimentation with human or animals participants.
Patient consent: Informed consent was obtained from the patient of the case reported.
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