Article
Polymorphous adenocarcinoma of the palate diagnosed during the COVID-19 pandemic
We present a case report on polymorphous adenocarcinoma of the palate diagnosed during the COVID-19 pandemic.
A 50-year-old female patient self-referred to the Restorative Dentistry department where she was consequently referred to the Maxillofacial Surgery team. The patient presented with an 8-week history of shooting pain and swelling in the upper left quadrant following three courses of antibiotics, which was thought to be due to an ill-fitting denture. She saw her general dental practitioner (GDP)prior to the lock down for the root canal treatment on UL4 and UL1. Past medical history indicated allergies to penicillin and gastro-oesophageal reflux disease, for which she was medicated with omeprazole. She had a history of smoking 20 cigarettes a day since the age of 16 and she enjoys alcohol socially.
Examination showed a denture that was looser than it should have been for its estimated age of 20 years. Clinically, there were no pathological palpable neck nodes and no evidence of diplopia. Her pupils were equal and reactive to light with no restriction of eye movement. No hyper globus was detected, although she did have some fullness in the infra-orbital region with no evidence of infra-orbital nerve paraesthesia.
Oral cavity examination demonstrated a partially dentate maxilla and mandible with a number of retained roots in the maxilla. A firm palpable mass was present in the maxillary vestibule extending from the pre-molar region to the first molar region. There was also an obvious expansion in the palate, which could be mistaken for denture-induced granuloma.
Incisional biopsy demonstrated a low-grade polymorphous adenocarcinoma of the left palate. CT imaging demonstrated an extensive maxillary tumour involving the pterygoid plates posteriorly, and the anterior and lateral walls of the maxilla. There was medial expansion across the midline but no overt orbital extension. The tumour however abutted the floor of the left orbit (Figure 1).
Polymorphous adenocarcinoma (PAC) is a malignant tumour that arises mainly from the minor salivary glands. In the recent update by the World Health Organization on the classification of salivary gland tumours, the term ‘low grade’ has been removed from polymorphous low-grade adenocarcinoma (PLGA) and the condition is now classified as polymorphous adenocarcinoma (PAC).
According to a review of the literature, PAC is the second most common intra-oral malignant minor salivary gland tumour. Palate and soft palate are the most common sites for PAC origination. It is more frequently seen in the sixth and seventh decade with a female predilection. In the differential diagnosis for a patient presenting with ill-fitting dentures, minor salivary gland tumours should be included. It is also important to carry out a thorough full-mouth examination to rule out any other pathology of the intra-oral tissues that may cause the dentures to become loose. Early diagnosis and prompt referral are mandatory as this could prevent the patient from having extensive surgical treatment required for most intra-oral malignancies.