Torre-Muir syndrome is an inherited condition characterized by the sebaceous (oil gland) skin tumors in association with the other forms of cancer. The basal cell carcinoma that is associated to develop as the result of sun exposure is also believed to occur among people with this syndrome. Some of the other types of skin changes associated with this condition include sebaceous adenomas, sebaceous carcinomas, sebaceous epitheliomas and keratoacanthomas. These affected individuals are also at increased risk of developing other forms of cancer evident in Lynch syndrome including the stomach, ovarian, small bowel, urinary tract, liver or bile duct and the prostate. The skin lesions can occur before or after the diagnosis of internal cancer.
Causes
Torre-Muir syndrome is a subtype of Lynch syndrome that develops as the result of the mutations in the MLH1, MSH2 or MSH6 gene which produces proteins required for the repairing of DNA. The proteins produced by these genes help fix the mistakes that occur when the DNA is copied before the cells divide. When the associated protein is either absent or nonfunctional, the DNA mistakes cannot effectively be repaired. As the result, the affected cells are unable to continue functioning normally and increase the risk of developing tumors. It is also possible that other genetic mutation may also play role in the development of this disease. This syndrome is inherited in an autosomal dominant pattern meaning one copy of the genetic mutation is sufficient to cause this condition.
Symptoms
A sebaceous adenoma is the commonly detected finding among individuals with Torre –Muir syndrome. The sebaceous carcinomas of the eyelid can invade the other parts of the body including the orbit of the eye causing death. Tumors occurring at other sites of the body can also spread to different parts but is unlikely to cause death. Although keratoacathomas can develop anywhere on the body, the common sites include the upper side of the hands and the face. Colorectal cancer is the most common form of internal cancer affecting around half of the cases. Other forms of cancer that can develop include lymphoma, leukemia, salivary gland tumors, chondrosarcoma and breast cancer.
Diagnosis
The diagnosis is based on the presence of one or more of the skin changes, the presence of one or more of internal cancer, family history of Lynch-related cancers and a personal history of Lynch-related cancers. The molecular genetic testing can detect the mutation responsible for developing this syndrome, although not all the cases present mutation in one of these genes. Other unidentified genetic mutation may also contribute to the development of this disorder.
Treatment
The affected individuals require appropriate laboratory and radiographic test to detect the internal malignancies. In the case cancer is detected, appropriate anti-cancer treatment should be initiated. The treatment for the skin lesions includes excision or cryotherapy for the benign tumors, sebaceous carcinomas need to be excised completely and use of oral retinoids may prevent some of the lesions. In some cases, genetic counseling may be beneficial for the affected individuals and their family members.
References
https://rarediseases.info.nih.gov/diseases/6821/muir-torre-syndrome/cases/30944
http://www.dermnetnz.org/topics/torre-muir-syndrome/
http://www.cancer.net/cancer-types/muir-torre-syndrome
