What are the other Names for this Condition? (Also known as/Synonyms)

• MTS (Muir-Torre Syndrome)
• Torre-Muir Syndrome 

What is Muir-Torre Syndrome? (Definition/Background Information)

• Muir-Torre Syndrome (MTS) is a rare, genetic disorder that is inherited in an autosomal dominant pattern. In this disorder, there is at least one sebaceous gland neoplasm on the skin and one malignancy of the internal organs, such as the colon, urinary bladder, stomach, etc.
• MTS mostly manifests during late middle-age and can present as skin tumors, abdominal pain, rectal bleeding, anemia, loss of appetite, and vomiting
• Once diagnosed, lifelong observation and treatment may be necessary to monitor the condition. The prognosis of Muir-Torre Syndrome depends upon the stage of diagnosis and prompt medical attention provided

Who gets Muir-Torre Syndrome? (Age and Sex Distribution)

• Muir-Torre Syndrome is a rare syndrome with an average presentation age of 55 years
• This disorder is observed more in males than females (in a 3:2 male-female ratio)
• MTS is seen worldwide and all racial and ethnic groups may be at risk

What are the Risk Factors for Muir-Torre Syndrome? (Predisposing Factors)

The risk factors of Muir-Torre Syndrome include:

• Family history (parents, brothers, and sisters) of colorectal cancer and sebaceous tumor is a risk factor
• Individuals with DNA mismatch repair defect
• Mutations in the MLH1 and MSH2 genes can increase the risk
• A family history of MTS, since this genetic condition can be passed from one generation to another

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Muir-Torre Syndrome? (Etiology)

Muir-Torre Syndrome is a genetic disorder caused by DNA mismatch repair defect.

• Mutation in the MLHI and MSH2 genes causes this syndrome. The syndrome is inherited as an autosomal dominant trait
• The MLH1 and MSH2 genes are located on chromosome 3
• These genes are involved in the repair of mistakes that occur, when DNA is copied during a cell division. The cells have a repair mechanism to rectify the errors made during cell division. Mutations affect the repair mechanism resulting in DNA with errors. These errors in DNA can result in cells becoming cancerous

Note: It is important to note that the presence of DNA mismatch repair genes mutation does not mean that individual will get colon cancer. It only indicates a higher predisposition to develop colon cancers.

Autosomal dominant: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly functioning gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition or pass it on to their offspring.

What are the Signs and Symptoms of Muir-Torre Syndrome?

The typical feature of Muir-Torre Syndrome is tumors of the sebaceous glands of the skin and internal malignancy (affecting any organ). In addition to sebaceous tumors, the syndrome can also have colon cancers, ovarian cancers, liver cancers, endometrial cancers, Hodgkin lymphoma, keratoacanthomas of skin, and genitourinary cancers.

The signs and symptoms of Muir-Torre Syndrome may include:

• Skin tumors that are yellowish bumps on the face, head, neck, and trunk. These are usually sebaceous adenomas, sebaceous epitheliomas, and sebaceous carcinomas
• Many individuals may have no symptoms, until they develop colon cancer
• Rectal bleeding
• Diarrhea
• Abdominal pain, abdominal mass
• Unexplained weight loss, loss of appetite
• Vomiting of blood
• Anemia, weakness, and fatigue
• Abnormal menstrual bleeding

Keratoacanthomas are tumors of the skin that are tan-colored or reddish in color; they occur as firm nodules.

How is Muir-Torre Syndrome Diagnosed?

The detection rate for mismatch repair gene mutations is less than 100%. Hence, a diagnosis of Muir-Torre Syndrome is made on clinical examination, family history, genetic testing, and immunohistochemical studies of sebaceous tumors of skin. The diagnostic tools may include:

• Comprehensive family history and a good physical exam
• Complete blood cell (CBC) count
• Digital rectal exam
• Carcinoembryonic antigen testing (for colon cancers)
• Liver function tests (may be abnormal in metastatic colon cancer to liver)
• Computed tomography (CT) scan of the abdomen and pelvis
• Special immunohistochemical analysis (IHC) called MSI (microsatellite assay) can be performed on formalin fixed paraffin embedded tumor blocks by the pathologist
• Follow-up genetic test is necessary, if IHC results indicate possible Muir-Torre Syndrome, due to positive microsatellite instability
• Screening colonoscopy with biopsy can help in determining the histologic type of polyps (such as adenomatous type as opposed to hyperplastic type of polyps)
• Fecal occult blood test (FOBT) to detect blood in stool (such as observed in colon cancer). The presence of blood in stools does not mean that individual has cancer. Blood in stool can be seen due to non-cancer causes too
• Double contrast barium enema can determine the presence of any mass
• In women:
  • Regular PAP smear
  • Regular mammogram
  • Regular pelvic examination with a endometrial biopsy, as clinically indicated

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Muir-Torre Syndrome?

The complications of Muir-Torre Syndrome may include:

• The polyps can develop into cancers, especially in the colon and endometrium
• The polyps can bleed

How is Muir-Torre Syndrome Treated?

Muir-Torre Syndrome is a genetic disorder and there is no cure for the condition. Efforts may be taken to decrease the complication due the genetic defects.

• If cancer of colon develops, then surgery remains the main option
• Prophylactic removal of the colon prior to the development of cancer is generally not recommended
• Screening colonoscopy is an effective measure to prevent colon cancer (or being alert to its development)
• Treatment of cancers as they develop through surgery, chemotherapy, and/or radiation therapy depending on the clinical situation
• Skin tumors can be surgically excised

How can Muir-Torre Syndrome be Prevented?

• Currently, there are no specific methods or guidelines to prevent Muir-Torre Syndrome, since it is a genetic condition
• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders
• At risk family members, who have not yet been genetically tested should undergo the following tests:
  • Annual colonoscopy
  • Annual gynecologic examinations
  • Screening for endometrial biopsy
  • Serum CA 125 test

What is the Prognosis of Muir-Torre Syndrome? (Outcomes/Resolutions)

• The prognosis of Muir-Torre Syndrome depends on the stage and type of tumor that develops
• Regular medical checkups can help detect cancers early, which when treated appropriately can increase life expectancy

Additional and Relevant Useful Information for Muir-Torre Syndrome:

Like Gardner syndrome and Peutz-Jeghers syndrome, Muir-Torre Syndrome is an example of skin-polyposis syndromes.