Muir–Torre syndrome

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Muir–Torre syndrome
Sebaceous adenoma - low mag.jpg
Micrograph of a sebaceous adenoma, as may be seen in Muir-Torre syndrome. H&E stain.
Classification and external resources
Specialty Lua error in Module:Wikidata at line 446: attempt to index field 'wikibase' (a nil value).
OMIM 158320
DiseasesDB 31385
eMedicine derm/275
Patient UK Muir–Torre syndrome
MeSH D055653
[[[d:Lua error in Module:Wikidata at line 863: attempt to index field 'wikibase' (a nil value).|edit on Wikidata]]]

Muir–Torre syndrome (MTS) is a rare hereditary, autosomal dominant cancer syndrome[1]:663 that is thought to be a subtype of HNPCC. Individuals are prone to develop cancers of the colon, breast, and genitourinary tract, and skin lesions, such as keratoacanthomas and sebaceous tumors. The genes affected are MLH1, MSH2, and more recently, MSH6, and are involved in DNA mismatch repair.

Symptoms

Muir-Torre Syndrome is characterized by both:[2]

  1. At least a single sebaceous gland tumor (either an adenoma, an epithelioma, or a carcinoma)
  2. A minimum of one internal malignancy

The Amsterdam criteria are frequently used to diagnose Lynch syndrome and Muir–Torre syndrome. They include the following:

  • 3 or more relatives with an HNPCC-associated cancer (i.e., colorectal, cancer of the endometrium, small bowel, ureter, or renal pelvis)
  • 2 or more successive generations affected by cancer
  • 1 or more persons with cancer is a first-degree relative of the other 2, at least 1 case of colorectal cancer younger than age 50 years, a diagnosis of familial adenomatous polyposis has been excluded, tumors are verified by histologic examination

Muir-Torre Syndrome is a genetic condition. Mutations in MLH1 and MSH2 are linked with the disease. These genes code for DNA mismatch repair genes, and mutations increase the risk of developing cancerous qualities.

Many patients who have sebaceous neoplasms with mutations in MSH2 and MLH1 do not in fact have Muir-Torre Syndrome. The Mayo Muir-Torre risk score was devised to improve the positive predictive value of immunohistochemistry and reduce the false positive rate.[3][4] The Mayo Muir-Torre Risk score assigns points based several characteristics. A score of 2 or greater has a high positive predictive value of Muir–Torre syndrome. A score of 1 or lower is less likely to be Muir–Torre syndrome.[3]

Age of onset of first sebaceous neoplasm: <60 years = 1 point, otherwise 0 points Total number of sebaceous neoplasms: 1 = 0 points, >2 = 2 points. Personal history of Lynch related cancers: No = 0 points, Yes = 1 point Family history of Lynch-related cancer: No = 0 points, Yes = 1 point

The most common internal malignancies associated with Muir–Torre syndrome are: Colorectal (56%), Urogenital (22%), Small Intestine (4%), and Breast (4%). A variety of other internal malignancies have been reported.[5]

Incidence

Muir-Torre was observed to occur in 14 of 50 families (28%) and in 14 of 152 individuals (9.2%) with Lynch Syndrome, also known as HNPCC.[6]

The 2 major MMR proteins involved are hMLH1 and hMSH2. Approximately 70% of tumors associated with the MTS have microsatellite instability. While germline disruption of hMLH1 and hMSH2 is evenly distributed in HNPCC, disruption of hMSH2 is seen in greater than 90% of MTS patients.[7]

Gastrointestinal and genitourinary cancers are the most common internal malignancies. Colorectal cancer is the most common visceral neoplasm in Muir–Torre syndrome patients.[8]

Treatment

Immunohistochemistry is now being used more often to diagnose patients likely to have Muir-Torre. Sebaceous neoplasms are only infrequently encountered, and immunohistochemistry is reliable and readily available, so researchers have recommended its use. Routine immunohistochemical detection of DNA mismatch repair proteins help identify hereditary DNA mismatch repair deficiency.[9]

Treatment of Muir-Torre normally consists of oral isotretinoin. The drug has been found to prevent tumor development.[10][11]

Patients with Muir–Torre syndrome should follow the same stringent screening for colorectal carcinoma and other malignancies as patient with Lynch-Syndrome. This includes frequent and early colonoscopies, mammograms, dermatologic evaluation, and imaging of the abdomen and pelvis.[12]

Eponym

It is named for EG Muir and D Torre. A British physician, Muir noted a patient with many keratoacanthomas who went on to develop several internal malignancies at a young age. Torre presented his findings at a meeting of the New York Dermatologic Society.[13][14]

It was not until the 1980s when Creighton professor Henry Lynch noted a clustering of Muir-Torre patients in families with Lynch Syndrome.[15]

Genetic Overlap with Turcot Syndrome

A couple studies have been conducted on patients with both Muir-Torre Syndrome and Turcot Syndrome. It is thought that the two may have some genetic overlap. Both have been associated defects in MLH1 and MSH2 genes.[16]

In one study, a patient with defective MSH2 and MSH6 mismatch repair genes exhibited both syndromes. This is the first case where a patient with genotypic changes consistent with HNPCC has been properly diagnosed with an overlap of both syndromes. Along with neoplasms of the sebaceous gland, this patient developed cerebral neoplasms, characteristic of Turcot Syndrome.[17]

See also

References

  1. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  2. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ 3.0 3.1 Roberts ME, Riegert-Johnson DL, Thomas BC, et al. A clinical scoring system to identify patients with sebaceous neoplasms at risk for the Muir-Torre variant of Lynch syndrome. Genet Med. 2014;16:711-16 doi:10.1038/gim.2014.19
  4. ↑ Roberts ME, Riegert-Johnson DL, Thomas BC, et al. Screening for Muir-Torre syndrome using mismatch repair protein immunohisochemistry of sebaceous neoplasms. J Genet Counsel. 2013;22:393-405. DOI 10.1007/s10897-012-9552-4
  5. ↑ Akhtar S, Oza KK, Khan SA, et al. Muir-Torre syndrome: a case report of a patient with concurrent jejunal and ureteral cancer and a review of the literature. J Am Acad Dermatol. 1999;41:681-6.
  6. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  7. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  9. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  10. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  11. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  12. ↑ Ponti G, Pnz de Leon M. Muir-Torre syndrome. Lancet Oncol 2005;6:980-87. PMID 16321766
  13. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  14. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  15. ↑ Lynch HT, Fussaro RM, Roberts L, et al. Muir-Torre syndrome in several members of a family with a variant of the Cancer Family Syndrome. Br J Dermatol. 1985;113:295-301
  16. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  17. ↑ Lua error in package.lua at line 80: module 'strict' not found.

External links

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