Polymorphous low-grade adenocarcinoma (PLGA) is a rare tumor of the salivary glands that is limited, to a great extent, to the minor salivary glands and commonly, but not exclusively, localized in the palate of the mouth. The major salivary glands are the parotid glands (at the side of the face, below the ears), the sublingual glands (below the tongue), and the submandibular glands (below the lower jaw). As the name suggests, each of the major salivary glands is of substantial size and visible to the naked eye. There are about 600 to 1,000 minor salivary glands that are microscopic in size. These minor salivary glands are found in the lining (mucosa) of the lips, tongue, and hard and soft palate, as well as inside the nose, cheeks, and sinuses.
Less than one (1%) per cent of all cancers reported in the USA are salivary cancers and, of these, 80% begin in the parotid glands, and about 15% begin in the submandibular glands, leaving only 5% that begin in the sublingual and minor salivary glands. Most of the tumors that start in the major salivary glands turn out to be benign, while most, but not all, of the cancers that start in the minor salivary glands turn out to be malignant.
A lump or mass in the palate or near any of the salivary glands should be seen by a physician as soon as possible. A lingering pain in the area of the salivary glands is a signal to see a physician. A change in the size and/or shape of one of the salivary glands (asymmetry) may be a sufficient reason to see a doctor. Unexplained bleeding in the mouth is also a symptom warranting attention, and any persistent numbness on any part of the face or a weakening of the muscles on one side of the face should be brought to the attention of a physician. Early diagnosis and treatment are important.
In most instances PLGA affects people in their middle age. The median age at which patients are diagnosed is 57 years, with a range of from 22 to 71 years. For reasons that are unknown, this disease affects slightly more women than men.
The diagnosis of PLGA may be suspected on history and clinical examination, but can be confirmed only by biopsy of the affected tissue.
The primary mode of treatment for low-grade stage I tumors of the salivary gland is surgery (resection). Radiation therapy may be prescribed as a supplement in some cases. Palate rehabilitation may be needed depending on the size of the tumor.
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