Clinicopathological relevance of the association between gastrointestinal and sebaceous neoplasms: the Muir-Torre syndrome

An Unusual Presentation of Synchronous Breast Cancer and Skin Malignancy in a Patient with Lynch Syndrome: A Case Report and Review of the Literature

BACKGROUND

Lynch syndrome is an autosomal dominant condition that leads to an increased risk of many neoplasms. In the United Kingdom, NICE recommends that patients with colorectal and endometrial cancer should be tested for Lynch syndrome. There is conflicting evidence in the literature on the link between breast cancer and Lynch syndrome.

CASE PRESENTATION

A 54-year-old woman presented with a lump in her right breast with a background of locally advanced colorectal cancer and Lynch syndrome due to a MLH1 gene mutation. A core biopsy showed a grade 3, invasive, triple-negative NST carcinoma. The tumour was triple-negative with patchy positivity for CK14 and CK5/6. Simultaneously, a cystic skin lesion in the contralateral breast was noted, which comprised lesional cells with a proliferation of clear cells and bland basaloid cells. The lesion had evidence of sebaceous differentiation with AR, podoplanin and p63 positivity. MSH1 and PMS2 deficiency was found in the breast and skin lesions.

CONCLUSIONS

In Lynch syndrome, it is vital to be aware of the increased risk of various types of cancer. This case adds to the body of evidence of the spectrum of malignancies that can be encountered in patients with Lynch syndrome.

Recurrent colon cancer in a patient with Muir-Torre syndrome: a case report

Muir-Torre syndrome (MTS) is a rare subtype of hereditary nonpolyposis colorectal cancer syndrome caused by a defect in DNA mismatch repair leading to microsatellite instability. It is characterized by the presence of at least one sebaceous gland tumor and one internal malignancy, most commonly colorectal and endometrial tumors. These patients have a high propensity for tumorigenesis, and while strict screening protocols are in place, there are only two cases that describe the management approach to recurrent colon cancer. Here, we present a case of recurrent colorectal cancer in a patient with MTS, and describe how it was managed at our facility by a multidisciplinary team.

Metastatic Prostatic Adenocarcinoma in Patient With Muir-Torre Syndrome Misdiagnosed as Metastatic Sebaceous Carcinoma: Case Report and Systematic Literature Review

Muir-Torre syndrome (MTS) is a rare autosomal dominant condition characterized by the presence of at least one cutaneous sebaceous tumor and one visceral malignancy, arising mostly from the gastrointestinal tract. We present the case of a 63-year-old man with several cutaneous and visceral neoplasias in the context of MTS, and a pelvic lymph node lesion diagnosed initially as metastatic sebaceous carcinoma, but later identified as metastasis from a newly diagnosed prostatic adenocarcinoma. Histological similarities between these 2 lesions are discussed. A systematic literature review was conducted evaluating all published cases of patients with MTS in which metastases were reported. Eighteen articles were included in the final synthesis, representing 20 patients with a total of 26 metastases. Seventeen patients (85%) exhibited metastases originating from MTS-related neoplasms, whereas only 2 patients (11%) exhibited metastases from concomitant malignancies. Of the 85% of patients with metastases from MTS-related malignancies, most originated from noncutaneous sources (78% from visceral neoplasms and 22% from sebaceous carcinomas). When stratifying according to metastases, 23 cases (88%) originated from MTS-related lesions, whereas only 3 (12%) originated from unrelated malignancies. Our findings thus demonstrate that most metastases found in MTS patients (88%) do indeed originate from MTS-related neoplasms. Nevertheless, it remains imperative that a broad differential diagnosis is maintained when assessing a novel lesion, to avoid misdiagnoses, as in the present case, with significant therapeutic and prognostic implications.

Role of microsatellite instability, immunohistochemistry and mismatch repair germline aberrations in immunosuppressed transplant patients: a phenocopy dilemma in Muir-Torre syndrome

Sebaceous tumours and keratoacanthomas are uncommon neoplasms that constitute important clinical criteria for Muir-Torre syndrome (MTS) diagnosis. In MTS patients, the increased risk of developing synchronous or metachronous visceral malignancies is characterised by autosomal dominant inheritance. However, there are further conditions, other than MTS, that increase the risk of sebaceous neoplasms, e.g. iatrogenic immunosuppression. In this latter scenario, the sebaceous tumours can present microsatellite instability (MSI) and loss of mismatch repair (MMR) proteins, characteristic of hereditary syndromes, even in the absence of MMR germline mutations. In this article, we examine transplant probands in which the immunosuppressive therapies unmask the MTS cutaneous phenotypes, showing MSI and loss of MMR protein expression, as demonstrated by immunohistochemistry (IHC). Furthermore, MMR genes sequencing analysis identified the presence of germline mutations in MTS-suspected individuals, in the absence of a visceral MTS phenotype. It is well known that immunosuppression plays a central role in the development of sebaceous tumours in both MTS and in non-syndromic settings. Sebaceous skin tumours' MSI status and IHC profiles can be influenced by epigenetic or iatrogenic factors; however, they constitute valuable tools and a cost-effective approach to screen individuals who otherways should undergo MMR genes direct sequencing in the context of immunosuppression. In this complex setting, the choice of the immunosuppressive drug becomes a critical decision for the management of both MTS and sporadic transplant patients, which may benefit from the administration of immunosuppressive drugs, resulting in a low impact on skin cancerogenesis.

Molecular pathology of skin neoplasms of the head and neck

CONTEXT

Skin neoplasms include the most common malignancies affecting humans. Many show an ultraviolet (UV)-induced pathogenesis and often affect the head and neck region.

OBJECTIVE

To review literature on cutaneous neoplasms that show a predilection for the head and neck region and that are associated with molecular alterations.

DATA SOURCES

Literature review.

CONCLUSIONS

Common nonmelanoma skin cancers, such as basal and squamous cell carcinomas, show a UV-induced pathogenesis. Basal cell carcinomas are characterized by molecular alterations of the Hedgehog pathway, affecting patched and smoothened genes. While squamous cell carcinomas show UV-induced mutations in several genes, driver mutations are only beginning to be identified. In addition, certain adnexal neoplasms also predominantly affect the head and neck region and show interesting, recently discovered molecular abnormalities, or are associated with hereditary conditions whose molecular genetic pathogenesis is well understood. Furthermore, recent advances have led to an increased understanding of the molecular pathogenesis of melanoma. Certain melanoma subtypes, such as lentigo maligna melanoma and desmoplastic melanoma, which are more often seen on the chronically sun-damaged skin of the head and neck, show differences in their molecular signature when compared to the other more common subtypes, such as superficial spreading melanoma, which are more prone to occur at sites with acute intermittent sun damage. In summary, molecular alterations in cutaneous neoplasms of the head and neck are often related to UV exposure. Their molecular footprint often reflects the histologic tumor type, and familiarity with these changes will be increasingly necessary for diagnostic and therapeutic considerations.

Immunosuppression and sebaceous tumors: a confirmed diagnosis of Muir-Torre syndrome unmasked by immunosuppressive therapy

Muir-Torre syndrome (MTS) is an autosomal dominant genodermatosis caused by mutations in the DNA mismatch repair genes MLH1 and MSH2. This case describes a patient with an extensive family history of colon cancer who experienced the onset of multiple sebaceous adenomas and carcinomas after undergoing kidney transplantation and receiving immunosuppressive therapy. The finding of deficient MSH2 expression in the immunohistochemical analysis of a sebaceous carcinoma prompted genetic testing for a systemic mutation in the mismatch repair gene. A systemic mutation of the MSH2 gene was detected and, despite the absence of a visceral malignancy, the diagnosis of MTS was made. Immunosuppression has previously been thought to play a possible role in unmasking a latent MTS phenotype in transplant recipients, but systemic mutations have not previously been analyzed. The relationship between immunosuppression and sebaceous tumors with the possibility of unmasking a MTS phenotype in transplant recipients is discussed.

Sebaceous neoplasia and the Muir-Torre syndrome: important connections with clinical implications

Sebaceous neoplasia comprises a spectrum ranging from benign to malignant. Proper histological identification is important for treatment, prognosis and potential association with the Muir-Torre syndrome (MTS). Our increased understanding of the significance and pathogenesis of these tumours has led to improved risk stratification, screening recommendations, and treatment of patients with an initial presentation of a sebaceous tumour. This review focuses on the diagnostic and histological features of sebaceous lesions, the MTS, and recent insights into the molecular pathogenesis of sebaceous tumours.

Oral manifestations of internal malignancy and paraneoplastic syndromes

Malignant tumors of visceral organs are a fundamental feature of familial cancer and paraneoplastic syndromes. In many instances, the presence of an internal and often occult malignancy may be forewarned by various external manifestations. Several of these findings are preferentially localized to the head and neck region, including the oral cavity proper. This places the dental practitioner in a unique position to detect these "markers" of occult neoplastic involvement. Because these markers may present before an established syndrome or cancer diagnosis, even representing the first expression of disease in some cases, early recognition by a dentist may lead to timely diagnosis and management of these cancer-associated syndromes.

Biological Behavior of the Sebaceous Carcinoma of the Head

BACKGROUND

The reports in the literature indicate that extraocular sebaceous carcinoma (SC), in contrast to orbital SC, is less aggressive and rarely metastasizes.

METHODS

Of 2422 epithelioma cases observed over 10 years, 8 (0.33%) resulted as histologically proven SCs, all of which were located in the head.

RESULTS

The clinical behavior of these tumors was observed by following patients for an average period of 50 months. Three of the tumors originated from the orbital region and five from other areas of the head (extraocular). In one case, the SC was associated with renal carcinoma (Muir-Torre syndrome). None of the orbital tumors metastasized, whereas two of the five cases of extraocular carcinoma metastasized to the locoregional lymph nodes.

CONCLUSION

It should be stressed that in this case study aggressive biologic behavior was observed in carcinoma arising from extraorbital areas.

Loss of DNA mismatch repair proteins in skin tumors from patients with Muir-Torre syndrome and MSH2 or MLH1 germline mutations: establishment of immunohistochemical analysis as a screening test

Muir-Torre syndrome (MTS) is a rare autosomal-dominant disorder characterized by the predisposition to both sebaceous skin tumors (or multiple keratoacanthomas) and internal malignancies. A subtype of MTS is allelic to hereditary nonpolyposis colorectal cancer and is caused by germline mutations in the DNA mismatch repair genes MSH2 or MLH1. In these cases both internal and skin tumors show characteristic microsatellite instability (MSI). The aim of the present study was to determine whether immunohistochemical examination of MSH2 or MLH1 protein expression in MTS-associated skin tumors can be used as a diagnostic screening tool to identify patients with germline mutations in MSH2 or MLH1. In the present study 28 skin lesions from 17 patients (20 sebaceous gland tumors, 4 sebaceous hyperplasias, 3 keratoacanthomas, and 1 squamous cell carcinoma) were tested immunohistochemically with antibodies against MSH2 and MLH1. Eighteen of these tumors were from eight patients with known MSH2 germline mutations, two tumors were from a patient with a germline mutation in MLH1, and eight microsatellite stable sporadic skin tumors served as controls. One sample had to be excluded because of a lack of immunoreactivity. All eight microsatellite stable tumors expressed both DNA repair proteins. In 15 of the tumors from MSH2 germline mutation carriers, loss of MSH2 expression was observed, one tumor showed reduced MSH2 expression, and one tumor displayed positive immunoreactivity to MSH2. Both tumors of the MLH1 germline mutation carrier showed loss of the MLH1 protein. In conclusion, our findings demonstrate that immunohistochemical testing of MTS-related skin tumors is a reliable screening method with high predictive value for the diagnosis of the DNA mismatch repair-deficient MTS.

MLH1 and MSH2 protein immunohistochemistry is useful for detection of hereditary non-polyposis colorectal cancer in young patients

AIMS

Hereditary non-polyposis colorectal cancer is related to germline mutations of DNA mismatch repair genes MLH1 and MSH2, which result in microsatellite instability and loss of protein expression of the corresponding mutated gene in the tumour tissue.

METHODS AND RESULTS

MLH1 and MSH2 protein expression was studied by immunohistochemistry in paraffin-embedded surgical samples of 100 colorectal adenocarcinomas occurring before 50 years of age. Absence of tumour cell nuclear staining with positive internal control (normal mucosa, lymphoid follicles) was considered negative. Loss of MLH1 or MSH2 expression was found in 20 cases with microsatellite instability in 15 cases. Twelve of these patients had a family history of colorectal cancer. Compared with MLH1- and MSH2-positive cases, MLH1- or MSH2-deficient colorectal adenocarcinomas were significantly associated on multivariate analysis with a younger age (38 vs. 43 years, P;0.0224), a larger tumour size (60 +/- 6 vs. 46 +/- 2 mm, P=0.0291), an expanding margin (85% vs. 51%, P=0.0159), a higher number of tumour-infiltrating lymphocytes assessed by CD3 immunostaining (202 +/- 48 vs. 33 +/- 4 CD3+ lymphocytes/10 high-power fields, P=0.0039), and a grade 2 Crohn's like lymphoid reaction (70% vs. 9%, P=0.0037). The two groups were not different for tumour site, differentiation, pTNM stage, vascular and perineural invasion, peripheral adenomatous residue, and 5-year survival rates.

CONCLUSIONS

MLH1- or MSH2-deficient colorectal carcinomas of young patients exhibit pathological and molecular features similar to hereditary non-polyposis colorectal cancer. This suggests that MLH1 and MSH2 immunohistochemistry is valuable for detecting hereditary non-polyposis colorectal cancer in young patients.

An association between sebaceous carcinoma and microsatellite instability in immunosuppressed organ transplant recipients

Sebaceous carcinomas are rare cutaneous appendageal tumors that may occur sporadically or in association with an internal malignancy in Muir-Torre syndrome. In Muir-Torre syndrome microsatellite instability can often be demonstrated in tumor DNA as a result of an inherited mutation in one of several known mismatch repair genes; however, the role of microsatellite instability in sporadic sebaceous carcinomas has not been previously studied. In this report we describe the clinicopathologic characteristics of a series of unselected sebaceous carcinomas and examine them for the presence of microsatellite instability. Of 10 consecutive tumors identified over a 10 y period, only one was from a patient known to have Muir-Torre syndrome. Of the nine presumed sporadic cases, five were from four renal transplant recipients and four from otherwise healthy individuals. Microsatellite instability was demonstrable in three cases: in the Muir-Torre syndrome-associated tumor and in two tumors from transplant patients. Microsatellite instability was subsequently also found in a sebaceous carcinoma from a further transplant patient prospectively sought from another institution. The presence of microsatellite instability in post-transplant sebaceous carcinomas was associated with loss of expression of the mismatch repair protein hMSH2. In summary, sebaceous gland carcinomas, while characteristic of Muir-Torre syndrome, are commonly found outside this context. Among presumed sporadic cases, our data suggest they may be over-represented in immunosuppressed renal transplant recipients. The presence of microsatellite instability in transplant-associated lesions, together with loss of hMSH2 expression suggests that immunosuppression might unmask a previously silent Muir-Torre syndrome phenotype in some cases. Alternatively, there is experimental evidence to suggest that immunosuppressive drugs, most plausibly azathioprine, could select for the emergence of a mutator phenotype and thus predispose to the development of sebaceous carcinomas. The role of mismatch repair defects in other post-transplant skin malignancies remains to be established.