Author: Vanessa Ngan, Staff Writer, 2005.
Torre-Muir syndrome is a rare inherited condition in which there are sebaceous (oil gland) skin tumours in association with internal cancer.
The most common organ involved is the gastrointestinal tract, with almost one half of patients having colorectal cancer. The second most common site is cancer of the genitourinary tract.
Torre-Muir syndrome is also known as ‘Muir-Torre syndrome’ and ‘sebaceous neoplasia/visceral carcinoma’.
Lynch syndrome is also known as hereditary non polyposis colorectal cancer (HNPCC). It is a rare genetic (autosomal dominant condition) that gives a predisposition to cancer of the lower gastrointestinal tract (colorectal), uterus (endometrium) and ovary. It is due to an inability to repair damaged DNA.
Research has shown that some families with Lynch syndrome share the same genetic fault as families with Torre-Muir syndrome. Torre-Muir syndrome is now considered part of the Lynch syndrome.
Skin lesions may occur before or after the diagnosis of the internal cancer. Sebaceous tumours are generally otherwise rare and their development should arouse suspicion of Torre-Muir or Lynch syndrome and the need for more investigative tests. The sebaceous neoplasms include:
Other skin lesions that may arise in affected family members include:
Torre-Muir syndrome and Lynch syndrome are autosomal dominant conditions due to genetic mutations, meaning half of an affected person's children also have the syndrome.
Mutations in 4 mismatch repair genes have been found in Torre-Muir and Lynch syndromes. These mostly involving the MSH2 gene, located on chromosome 2p. Some patients have mutations in the MLH1 gene on chromosome 3p.
Torre-Muir syndrome is usually suspected because of the clinical features. However, if a sebaceous adenoma, a sebaceous carcinoma or colonic polyp is removed surgically, the pathologist may examine the cells to see whether the MSH gene products have microsatellite instability, a characteristic of the syndrome.
Patients with Torre-Muir and Lynch syndrome need to undergo medical and physical examinations and appropriate laboratory and radiographic tests on a regular basis to check for internal malignancies, particularly of the gastrointestinal and genitourinary tracts. Patients need regular colonoscopy for early detection of colorectal tumours. Cancers should be managed with appropriate anti-cancer therapies.
In some families genetic diagnosis can identify asymptomatic carriers of the mutation. All first-degree relatives, especially mutation carriers, should be referred from the age of 20 years for routine follow-up and early treatment
Treatment of the skin lesions includes:
Improvement of Torre-Muir syndrome has been noted in patients treated with sirolimus.
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