Lynch syndrome with exclusive skin involvement: time to consider a molecular definition?

Muir-Torre syndrome (MTS) is clinically characterized by the occurrence of skin, usually sebaceous, and visceral tumors in the same individual. The most common underlying mechanism is a constitutional defect of the mismatch repair (MMR) genes that cause Lynch syndrome (LS). Herewithin we report on a 76 years-old male patient heterozygous for a pathogenic MSH2 missense substitution who presented with a striking cutaneous phenotype in the absence of typical LS visceral tumors. The patient developed 20 skin tumors, including sebaceous adenomas/carcinomas and keratoacanthomas. Two skin tumors showed immunohistochemical loss of MSH2 and MSH6 expression. There was no apparent family history of neoplasia. Based on the variable involvement of the skin and internal organs, we suggest that the definition of tumor associations that are often observed as variants of inherited tumor syndromes, such as MTS, should be guided by the underlying molecular bases. In addition, the presence of multiple sebaceous tumors, especially if showing MMR deficiency, appears to be a very strong indicator of a constitutional MMR gene defect. The reasons underlying the high phenotypic variability of cutaneous phenotypes associated with constitutional MMR defects are yet to be determined.

The cutaneous manifestations of gastrointestinal malignancy.

The skin is often the herald of an underlying systemic illness, and gastrointestinal malignancies can present in numerous ways in the skin. Paraneoplastic phenomenon, such as acanthosis nigricans and tripe palm, may be the first indicator of a gastrointestinal malignancy. In addition, gastrointestinal cancers can metastasize to the skin, as described in the well-known Sister Mary Joseph's nodule. Inflammatory systemic conditions such as dermatomyositis and multicentric reticulohistiocytosis can be associated with underlying malignancy. Finally, in numerous genetic syndromes with underlying malignancies, such as Muir-Torre, recognition of the skin signs leads to early diagnosis and screening.

[The tip of the iceberg: multiple cutaneous sebaceous tumor in colon cancer. Muir-Torre syndrome--case report]. / A jéghegy csúcsa: multiplex faggyúmirigy-eredetu bortumor coloncarcinomában. Muir-Torre-szindróma.

Muir-Torre syndrome is a rare genodermatosis with autosomal dominant inheritance. The syndrome is considered to be a subtype of the hereditary nonpolyposis colorectal cancer (or Lynch-syndrome). In two-third of the cases, it develops as the consequence of germline mutations in mismatch-repair genes--most commonly MutS Homolog-2 and MutL Homolog-1. Its diagnosis can be established if at least one sebaceous tumor (sebaceoma, sebaceous adenoma, epithelioma, carcinoma or basal-cell carcinoma with sebaceous differentiation) and/or keratoacanthoma and at least one internal neoplasm are present. Here the authors present the history of a 52-year-old man with multiple sebaceous carcinomas on his back. Immunohistochemical analysis showed the lack of MutL Homolog-1 protein expression in the tumor cells. Detailed clinical workup in order to identify internal malignancy found malignant coecum tumor. Histopathological evaluation of the sample from the right hemicolectomy revealed mid-grade adenocarcinoma with MutL Homolog-1 and postmeiotic segregation increased-2 deficiency. The detection of the cutaneous sebaceous carcinoma and the application of the modern diagnostic methods resulted in identification of the associated colorectal cancer in an early stage; hence, definitive treatment was available for the patient.

A clinical scoring system to identify patients with sebaceous neoplasms at risk for the Muir-Torre variant of Lynch syndrome.

PURPOSE: The Muir-Torre syndrome variant of Lynch syndrome is characterized by the presence of sebaceous neoplasms (adenoma, epithelioma/sebaceoma, carcinoma) and Lynch syndrome-associated cancers (colon, endometrial, and others). Several clinical scoring systems have been developed to identify patients with colon cancer at high risk of Lynch syndrome. However, no such system has been described for patients presenting with sebaceous neoplasms. METHODS: Based on logistic regression analysis, a scoring system was developed for patients with sebaceous neoplasm to identify those with the highest likelihood of having Muir-Torre syndrome. The final version of the scoring system included variables such as age at presentation of initial sebaceous neoplasm, total number of sebaceous neoplasms, personal history of a Lynch-related cancer, and family history of Lynch-related cancers. RESULTS: Patients with a score of 3 or more were more likely to have Muir-Torre syndrome (28 of 29 patients), those with a score of 2 had intermediate likelihood (12 of 20 patients), and no patient with a score of 0 or 1 was diagnosed with Muir-Torre syndrome. CONCLUSION: The Mayo Muir-Torre syndrome risk scoring system appears to identify whether patients who present with sebaceous neoplasms are in need of further Lynch syndrome evaluation using easily ascertained clinical information. Abnormal mismatch repair gene immunohistochemistry of a sebaceous neoplasm is a poor predictor in regard to diagnosing Lynch syndrome.

Muir-Torre syndrome: case report and review of the literature.

Muir-Torre syndrome (MTS), a subtype of Lynch syndrome II, presents as at least one internal malignancy associated with at least one sebaceous skin tumor. This autosomal-dominant genetic disorder is thought to arise from microsatellite instability. Although not all patients with sebaceous tumors have MTS, even a single biopsy-proven sebaceous adenoma may warrant evaluation for MTS. We report the case of a 76-year-old man with a marked family history of colon cancer; a personal history of colon cancer status post-partial resection of the colon; and multiple cutaneous neoplasms including sebaceous adenomas, sebaceous gland hyperplasia, and basal and squamous cell carcinomas. We review the literature describing MTS and highlight the important role of dermatologists and dermatopathologists in the potential early detection and initial diagnosis of this familial or hereditary colon cancer in patients presenting with cutaneous sebaceous adenomas. Correct diagnosis may be lifesaving in patients with MTS and their at-risk relatives who would benefit from earlier colonoscopy, tumor surveillance, and potential early cancer detection. Muir-Torre syndrome represents yet another dermatologic symptom of an internal disease.