From Volume 46, Issue 7, July 2019 | Pages 684-685
This case report demonstrates the management of a myoepithelioma in the minor salivary glands of the palate. Myoepitheliomas are rare, benign, salivary gland tumours which usually affect the parotid glands. The rare neoplasms only account for 1–1.5% of all salivary gland neoplasms. This case shows a minimal approach to treating this rare tumour found in a rare site.
Myoepitheliomas are rare, benign, salivary gland tumours which usually affect parotid glands and account for 1–1.5% of all salivary gland neoplasms.1 This case demonstrates how rapid epithelial recovery within the oral cavity and, despite the large resection site, excellent restoration of form and function can be achieved without the need for free flap reconstruction.
A 27 year-old male presented to the University Hospital of South Manchester maxillofacial department with a five year history of a large lump in the left palate. The patient reported that there was no noticeable change in size, no bad taste and no associated discharge or pain. This resulted in a late presentation as the patient was very relaxed about said ‘lump’. The patient was otherwise fit and healthy; a non smoker and only a social drinker.
When examined, the sessile lesion measured 31 x 23 x 20 mm and had a mixed consistency where some portions were fluctuant and some firm. As seen in Figure 1, the colour of the lesion also varied. No associated ulceration or mobility of associated teeth was found, with the patient reporting no nasal discharge, epistaxis or obstruction. Based upon these clinical findings, differential diagnoses were pleomorphic adenoma, a malignant salivary tumour (such as mucoepidermoid carcinoma) and other odontogenic causes, such as abscess or cyst.
Further investigations of MRI and OPG were undertaken. An MRI neck with contrast was ordered to rule out any lymphadenopathy, as well as any effect on immediate surrounding structures (Figure 2). The OPG was found to be unremarkable. The MRI with contrast found an enhancing submucosal lesion of the left hard palate with no malignant features and no erosion into the maxillary cortex.
The fine needle aspiration of the lesion found plasma-cytoid type myoepithelial cells consistent with either cellular pleomorphic adenoma or myoepithelioma, with an overall impression of a low grade salivary gland neoplasm and no signs of malignancy. To confirm the diagnosis an incisional biopsy was taken. This confirmed the lesion as a myoepithelioma with no malignant features but an excision with a wide margin was the recommended treatment.
The tumour was resected with an extra-capsular approach under general anaesthetic. The tumour was excised with 4 mm margins down to bone, with the left greater palatine artery being identified and ligated. A portion of margin was involved indicating incomplete excision. However, as this margin, was ‘deep to bone’ no further excision was indicated.
The resection, though extensive, did not require reconstruction but was treated with a minimally invasive approach, which consisted of a Coe-Pak dressing with a palatal cover plate. This allowed the site to heal by secondary intention without compromising on functional results.
There are four possible different morphological patterns of myoepitheliomas:1
The cellular pattern of these tumours are formed of plasmacytoid cells, spindle cells, epithelioid and clear cells. In the oral cavity, plasmacytoid cells are seen most commonly.2 Myoepithelioma needs to be separated from its malignant counterpart: that is more aggressive and will most likely re-occur after treatment. This was indicated by the biopsy which showed no cellular necrosis, cellular pleomorphism, invasive growth pattern or increased mitotic figures.3 The mass also showed no erosion, which further indicated a benign tumour. The treatment indicated was wide local excision to prevent re-occurrence and possible malignant transformation in the future. The biopsy confirmed the differential diagnosis. In similar case reports of the treatment of these tumours at the palatal site, the operative site is closed with sutures to enable primary closure. However, in this case, the site was allowed to close with secondary intention with favourable results being achieved (Figures 3 and 4).4
In this case, a good history plus thorough clinical and radiological investigations allowed a prompt diagnosis and successful treatment to be undertaken. The patient will continue to be reviewed for a period of 2 years.
