Muir-Torre Syndrome

Updated: Oct 01, 2020
  • Author: Victor G Prieto, MD, PhD; Chief Editor: Dirk M Elston, MD  more...
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Overview

Background

In 1967, Muir and Torre each reported patients with multiple cutaneous tumors along with visceral malignancies. Muir-Torre syndrome (MTS) is the combination of neoplasms of the skin (usually sebaceous adenoma, sebaceous epithelioma, or sebaceous carcinoma but also keratoacanthoma) and a visceral malignancy (usually colorectal, endometrial, small intestine, and urothelial). [1]

MTS has an autosomal dominant pattern of inheritance in 59% of cases and has a high degree of penetrance and variable expression. [2, 3, 4, 5]

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Pathophysiology

Muir-Torre syndrome (MTS) is considered to be a subtype of HNPCC. [6, 7] This condition is associated with an inherited defect in one copy of a DNA mismatch repair gene (MMR), which leads to microsatellite instability. [8] 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. [9] Two other proteins involved in MTS are MSH6 and PMS2.

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Etiology

See Pathophysiology. The main anomaly detected in  Muir-Torre syndrome (MTS) patients is the alteration in the mismatch repair genes, particularly MSH2 on chromosome 2 and MLH1 on chromosome 3. [10] Other genes are MSH-6, MLH-3, and PMS-2. [11] Loss of 2 of the retinoid receptors (RXR-beta and RXR-gamma) seems apparent in sebaceous carcinoma. [12]

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Epidemiology

Frequency

Muir-Torre syndrome (MTS) is a rare disorder, [13] with approximately 200 patients reported. Families with MTS are probably more common than reported.

Sex

MTS occurs in both sexes, with a male-to-female ratio of 3:2.

Age

The patient's age at presentation of MTS ranges from young adulthood to elderly patients, with a median age of 53 years. [14]

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Prognosis

Sebaceous carcinoma is an aggressive neoplasm, which can recur locally after excision and can metastasize. When local recurrences develop, they usually do so within the first five years of excision. Recurrence rates are estimated to be around 30% range. [15]

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Patient Education

Relatives of patients should receive genetic counseling.

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