Polymorphous Low-Grade Adenocarcinoma

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Polymorphous Low-Grade Adenocarcinoma is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • PLGA
  • Lobular Carcinoma of the Minor Salivary Glands
  • Low-Grade Papillary Carcinoma of the Palate
  • Pleomorphic Adenoma
  • Terminal Duct Carcinoma

Disorder Subdivisions

  • None

General Discussion

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.


Why a normal cell becomes malignant is not yet fully understood.

Affected Populations

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.

Standard Therapies


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.

Investigational Therapies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:




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For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into myCigna.com. For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html.