Polymorphous low-grade adenocarcinoma of the head and neck

Polymorphous low-grade adenocarcinoma is an entity described in 1984. An increasing number of reports in the pathology literature since then have identified this as the second or the third most common minor salivary gland malignancy. The natural history of polymorphous low-grade adenocarcinoma is distinct from other malignant salivary tumours. The present review will identify the diagnostic difficulties, the treatment options and the treatment outcome of this tumour.

Polymorphous low-grade adenocarcinoma is a slow-growing tumour that is locally invasive. The most common presentation is that of a lump in the oral cavity, usually on the palate. Diagnosis is established after a biopsy because cytological studies are not helpful. The morphological features can resemble pleomorphic adenoma and adenoid cystic carcinoma. Therapy is primarily wide surgical resection. The role of radiation therapy is not clear in the management of polymorphous low-grade adenocarcinoma. Metastases are rare and recurrences tend to occur more than 5 years after treatment, underlining the need for long-term follow-up. Recurrences can be successfully salvaged in more than 50% of the cases.

Polymorphous low-grade adenocarcinoma is primarily a pathologic diagnosis. Surgical resection is the mainstay of treatment. Long-term follow-up of 10 years or more is essential to ensure local control.