Muir-Torre Syndrome

Updated: Mar 11, 2025
  • 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]  Relatives of patients should receive genetic counseling.

Pathophysiology

MTS is considered to be a subtype of hereditary nonpolyposis colorectal cancer (HNPCC; Lynch syndrome). [5, 6] It is associated with an inherited defect in one copy of a DNA mismatch repair (MMR) gene (MMR), which leads to microsatellite instability. [7] The two major MMR proteins involved are hMLH1 and hMSH2. Approximately 70% of tumors associated with the MTS have microsatellite instability. In HNPCC, germline disruption of hMLH1 and hMSH2 is evenly distributed; however, in MTS, disruption of hMSH2 is seen in more than 90% of patients. [8] Two other proteins involved in MTS are MSH6 and PMS2.

Etiology

The main anomaly detected in MTS patients is the alteration in the MMR genes, particularly MSH2 on chromosome 2 and MLH1 on chromosome 3. [9, 10, 11] Other genes are MSH6, [12] MLH3, and PMS2. Loss of two of the retinoid receptors (RXR-beta and RXR-gamma) seems apparent in sebaceous carcinoma. [13] (See Pathophysiology.)

Epidemiology

MTS is a rare disorder, [14] with only a few hundred patients reported. Families with MTS are probably more common than has been reported. Patient age at presentation of MTS ranges from young adulthood to advance age (median age, 53 y). [15]  MTS occurs in both sexes, with a male-to-female ratio of 3:2.

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 5 years of excision. Recurrence rates have been estimated to be around 30%. [16]  A two-center study (N = 63; 67 cases; 7 MTS cases) found that independent predictors of recurrent sebaceous carcinoma included noncomplete circumferential peripheral and deep margin assessment methods and large lesion size, but not anatomic subtype or MTS status. [17]

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