Cutaneous sebaceous neoplasms as markers of Muir-Torre syndrome: a diagnostic algorithm

Molecular landscape of eyelid sebaceous gland carcinoma: A comprehensive review

Eyelid sebaceous gland carcinoma (SGC) is an aggressive skin cancer characterized by a heightened risk of recurrence and metastasis. While surgical excision is the primary treatment, unraveling the molecular intricacies of SGC is imperative for advancing targeted therapeutic interventions and enhancing patient outcomes. This comprehensive review delves into the molecular landscape of eyelid SGC, emphasizing key genetic alterations, signaling pathways, epigenetic modifications, and potential therapeutic targets. Significant findings include aberrations in critical signaling pathways (β-catenin, lymphoid enhancer binding factor, hedgehog, epidermal growth factor receptor, P53, and P21WAF1) associated with SGC progression and poor prognosis. Notably, eyelid SGC manifests a distinctive mutational profile, lacking ultraviolet signature mutations in tumor protein 53 (TP53), indicating alternative mutagenic mechanisms. Next-generation sequencing identifies actionable mutations in genes such as phosphatase and tensin homolog (PTEN) and Erb-B2 receptor tyrosine kinase 2 (ERBB2), facilitating the emergence of personalized medicine approaches. Molecular chaperones, specifically X-linked inhibitor of apoptosis protein (XIAP) and BAG3, emerge as pivotal players in promoting tumor survival and proliferation. The review underscores the role of epithelial-mesenchymal transition, where regulators like E-cadherin, vimentin, and ZEB2 contribute to SGC aggressiveness. Epigenetic modifications, encompassing DNA methylation and microRNA dysregulation, further elucidate the molecular landscape. This review consolidates a comprehensive understanding of the molecular drivers of eyelid SGC, shedding light on potential therapeutic targets and providing a foundation for future investigations in diagnostic, prognostic, and personalized treatment strategies for this formidable malignancy.

Muir-Torre Syndrome: A Case Report and a Literature Review of Genetic Insights and Cancer Surveillance

Muir-Torre syndrome (MTS) is a rare autosomal dominant genetic disorder that manifests through the co-occurrence of sebaceous skin tumors and internal malignancies, primarily due to mutations in mismatch repair (MMR) genes such as MSH2, MLH1, and MSH6. This paper presents a detailed case report of a 57-year-old female diagnosed with MTS, highlighting her extensive medical history and the critical role of genetic testing and multidisciplinary management. The patient's dermatological and oncological assessments revealed multiple sebaceous carcinomas and recurrent urothelial carcinoma, confirmed by a pathogenic MSH2 mutation. Through comprehensive preventive surgeries and rigorous follow-up, this case underscores the necessity of proactive cancer surveillance. The discussion integrates findings from key genetic studies and emphasizes the importance of immunohistochemistry in diagnosis. Recommendations for clinical practice include routine genetic testing, stringent surveillance, and multidisciplinary management, underscoring the need for ongoing research to understand better and manage this complex syndrome.

Germline Testing of Mismatch Repair Genes Is Needed in the Initial Evaluation of Patients With Muir-Torre Syndrome-Associated Cutaneous Sebaceous Neoplasms: A Case Series

Muir-Torre syndrome, a subtype of Lynch syndrome, is characterized by a germline mutation of one or more mismatch repair genes such as MutL Homolog 1 (MLH1), MutS Homolog 2 (MSH2), MutS Homolog 6 (MSH6), and PMS1 Homolog 2, mismatch repair system component (PMS2) resulting in microsatellite instability and at least one malignancy and a minimum of one syndrome-associated sebaceous neoplasm such as a sebaceous adenoma, epithelioma, or carcinoma. The syndrome has an autosomal dominant mode of inheritance detectable with germline sequencing of normal body elements such as blood, saliva, or normal skin for a mismatch repair gene mutation. Sebaceous neoplasms can occur before, concurrent with, or following Muir-Torre syndrome-related cancer. Immunohistochemistry, microsatellite instability testing, and next-generation sequencing of tumor tissue can evaluate malignancies such as colorectal and endometrial cancer and sebaceous neoplasms for somatic mismatch repair gene defects. However, these tests cannot differentiate somatic (acquired) versus germline alterations, and immunohistochemistry and microsatellite stability assessment can produce false negatives. Finally, the Mayo Muir-Torre syndrome risk score algorithm cannot always reliably determine which patient with a new sebaceous neoplasm should have germline testing. We report three men who presented with a Muir-Torre syndrome-associated sebaceous neoplasm: a 67-year-old male with no personal or family history of cancer who presented with a chest sebaceous carcinoma with MSH2 and MSH6 gene expression loss on immunohistochemistry and a Mayo Muir-Torre syndrome risk score of 0 who declined germline testing; a 74-year-old male with Janus kinase 2 (JAK2)-related myelodysplastic syndrome, yet no history of a Lynch syndrome-associated cancer, who developed a sebaceous epithelioma on his leg with PMS2 gene expression loss by immunohistochemistry and, although Mayo Muir-Torre syndrome risk score was only 1 (suggests no likelihood of a Lynch syndrome germline mismatch repair gene mutation), germline testing demonstrated a PMS2 alteration; and a 59-year-old male with a germline-confirmed MLH1-associated Lynch syndrome and a prior colon carcinoma, who developed a sebaceous adenoma on his nostril that unexpectedly demonstrated preservation of normal MLH1 staining (reflecting a false negative) by immunohistochemistry. In summary, these cases are consistent with the literature suggesting that tumor immunohistochemistry and microsatellite stability testing can miss germline alterations. Hence, we recommend that the initial evaluation of a patient with even a single new Muir-Torre syndrome-associated sebaceous neoplasm should include germline mismatch repair gene mutation testing. Finding a mismatch repair gene germline mutation should prompt genetic counseling, initial and future cancer screening recommendations, and germline testing of family members.

A retrospective cohort study of genetic referral and diagnosis of lynch syndrome in patients with cutaneous sebaceous lesions

Immunohistochemistry (IHC) of cutaneous sebaceous lesions (SL) can be used to screen patients for Lynch syndrome (LS). There is little data on rates of genetic referral and outcomes of genetic testing for patients with SL. This single-center retrospective study characterizes 400 + patients with SL, including IHC results, genetics referrals, and outcomes of genetic testing. Retrospective chart reviews were performed for patients with a pathology-confirmed diagnosis of SL at the University of Michigan between January 2009 and December 2019. 447 patients with 473 SL were identified. Excluding 20 patients with known LS, IHC was conducted in 173 (41%) patients. 92/173 (53%) patients had abnormal results. 69 of these 92 (75%) patients were referred to genetics. 32 additional patients were referred with normal IHC (n = 22) or without IHC (n = 10). Of 101 patients referred, 65 (64%) were seen and 47 (47%) completed genetic testing. 7/47 (15%) had pathogenic variants associated with LS, six with concordant abnormal IHC and one without IHC. Cancer genetics referral of patients with SL, particularly for lesions with abnormal IHC, yields a significant rate of LS diagnosis. Providers should consider genetics referral for patients with SL.

Clinical and Molecular Features of Skin Malignancies in Muir-Torre Syndrome

BACKGROUND

We investigated the mutational landscape of skin tumors in patients with Muir-Torre Syndrome (MTS) a hereditary autosomal dominant mismatch repair disorder of increased cancer susceptibility, and examined mutations other than in the DNA mismatch repair (MMR) genes.

METHODS

This retrospective single-center case series included seven patients with the diagnosis of Muir-Torre Syndrome with precise medical history and family history. Mutational analysis of tumor samples Formalin-fixed paraffin-embedded tissue blocks of skin lesions associated with Muir-Torre Syndrome were used for further analysis. All skin tumors were analyzed with the Oncomine Comprehensive Assay v3 (Life Technologies), which includes 161 of the most relevant cancer driver genes.

RESULTS

Eleven skin neoplasms (nine sebaceous tumors, one melanoma, one cutaneous squamous cell carcinoma) were diagnosed in seven patients. In two patients, visceral malignancies preceded the diagnosis of the skin tumors and one patient was diagnosed with a visceral malignancy after a sebaceous tumor. History of familial cancer of Lynch Syndrome (LS) was reported in three patients. The most frequently detected mutation was in the MSH2 gene, followed by mutations in the NOTCH1/2 and TP53 gene. Conclusion, this study provides a molecular analysis of Muir-Torre Syndrome associated and non-associated skin tumors in patients with Muir-Torre Syndrome. Patients with sebaceous lesions should undergo microsatellite instability analysis and accurate evaluation of personal and family history to detect a possible Muir-Torre syndrome. As secondary malignancies may appear years after the first occurrence of sebaceous tumors, lifelong screening is mandatory.

Comparison of adipophilin and recently introduced PReferentially expressed Antigen in MElanoma immunohistochemistry in the assessment of sebaceous neoplasms: A pilot study

BACKGROUND

We and others have noticed consistent staining of sebaceous glands with PReferentially expressed Antigen in MElanoma (PRAME). We aimed to determine whether PRAME was as sensitive, specific, and interpretable as adipophilin for distinguishing sebaceous neoplasms (SNs) from other neoplasms.

METHODS

Twenty SNs and 32 control cases were stained for PRAME and adipophilin. Extent of staining was scored as follows: 0, no staining; 1, <5% positivity; 2, 5% to 50% positivity; and 3, >50% positivity. Intensity was scored as negative, weak, moderate, or strong. A composite score was determined by adding the scores for extent and intensity.

RESULTS

PRAME had positive composite scores in all 20 SNs in the more differentiated areas, whereas adipophilin had positive composite scores in 19/20 cases. PRAME showed positivity in the basaloid cells in 15/16 cases, whereas adipophilin was positive in 14. Among controls, PRAME and adipophilin had positive composite scores in 3/32 cases and 6/32 cases, respectively.

CONCLUSIONS

PRAME and adipophilin are comparable in terms of distribution and intensity for staining sebocytes. In the basaloid cells, PRAME expression is often more diffuse and easier to detect than adipophilin. In comparing the SNs to the controls, PRAME was more sensitive and more specific than adipophilin. PRAME could be used as an additional marker of sebaceous differentiation in everyday practice.

A Case of Muir-Torre Syndrome

Muir-Torre syndrome (MTS) is an autosomal dominant condition characterized by dermatological tumors along with visceral malignancies. The dermatological manifestations include recurrent sebaceous adenomas and keratoacanthomas. The commonly seen visceral malignancies are colorectal, gynecological, and urological. It is a variant of hereditary non-polyposis colorectal carcinoma syndrome (HNPCC). The underlying genetic mechanism is germline mutations in the DNA mismatch repair (MMR) genes leading to microsatellite instability (MSI), conferring an increased risk of developing malignancies. This is a case of a 57-year-old male patient with a history of colon cancer diagnosed at age 32 and multiple sebaceous adenomas. The patient also has a strong family history of cancer. They were referred to oncology after the immunohistochemical staining of a sebaceous adenoma showed loss of expression for MSH2 and MSH6. Next-generation sequencing identified a mutation in the MSH2 gene. These patients require genetic testing, counseling, and close follow-up with regular screening for cancer.

Ocular Adnexal Adenomatoid Sebaceous Gland Hyperplasia: A Clinical and Immunopathologic Analysis in Relation to the Muir-Torre Syndrome

The purpose of this study is to codify the microscopic diagnostic criteria for ocular adnexal brow and caruncular sebaceous gland hyperplasias (pseudoadenomatoid) that distinguish it from an adenoma. Clinical records and photographs were critically reviewed and microscopic slides were stained with hematoxylin and eosin and immunochemically stained for adipophilin, androgen receptor, p16, p53, a spectrum of cytokeratins, Ki-67 and mismatch repair nuclear protein expression for MLH1, MSH2, PMS2, and MSH6. The patients and their close relatives had no history of cancer. Cytokeratin 7 and especially cytokeratin 17 highlighted the presence of ducts in the hyperplastic lesion, which are not present in adenomas. p16 and p53 were negative and Ki-67 immunostaining demonstrated similar low proliferation indices for normal and hyperplastic glands. The mismatch repair nuclear protein expressions were preserved in both lesions. Histopathologic misdiagnosis of adenomatoid sebaceous gland hyperplasia as an adenoma can lead to the impression of an association with the Muir-Torre syndrome. Cytokeratins 7 and 17 immunostaining can be helpful in highlighting compressed ducts that in exuberant sebaceous gland hyperplasias may lead to a diagnosis of an adenoma (in which ducts are absent). Negative immunostaining for p16 rules out a possible etiologic role of human papillomavirus in hyperplasias and the negative p53 staining indicates the lesions are not truly neoplastic. The preservation of mismatch repair nuclear protein expression rules out the likelihood of the Muir-Torre syndrome. The current cases convincingly establish that sebaceous hyperplasia is not associated with the Muir-Torre syndrome by both clinical findings and immunohistochemical testing.Two yellow lesions, from the brow and caruncle, were examined microscopically and immunohistochemically to establish the diagnosis of sebaceous gland hyperplasia and to rule out the Muir-Torre syndrome.

[Cancer-associated genodermatoses]

Hereditary tumor syndromes are characterized by a familial occurrence of tumors/cancer. A hereditary tumor syndrome should be suspected if a familial occurrence of cancer is seen and/or persons at younger age are affected. Some of the currently known tumor syndromes are associated with specific skin symptoms that can aid the physician in establishing the correct diagnosis. Examples are fibrofolliculoma in Birt-Hogg-Dubé syndrome, epidermal cysts, sebaceous cysts, neurofibroma in Gardner syndrome and sebaceous neoplasms or keratoacanthoma in Muir-Torre syndrome. If a genetic tumor syndrome is suspected, genetic testing and counselling should be performed in the index patient and is also recommended for family members. Affected patients should be offered regular clinical surveillance by the appropriate medical disciplines. Since curative therapy does not exist so far, preventive screening is of great importance.

Intraductal sebaceous papilloma of a meibomian gland: a new entity possibly associated with the MSH6 subtype of the Muir-Torre syndrome

Over several months, a painless, multinodular, non-erythematous swelling of the deep tissues of his left upper eyelid developed in a 63-year-old man. An excisional biopsy with histopathologic evaluation disclosed a unique sebaceous papilloma within a cyst lined by non-keratinizing squamous epithelium that focally displayed a variably thick, superficial, eosinophilic cuticular layer. Immunohistochemical staining demonstrated that the tumor and its epithelial cystic lining had a profile consistent with Meibomian gland duct epithelium. Adipophilin highlighted cytoplasmic vacuolar lipid positivity. The encapsulation of the lesion, absence of nuclear atypia, and Ki-67 nuclear positivity restricted to the basilar cells established its intrinsically benign nature. The patient's clinical history was remarkable for pulmonary and colonic carcinomas resected, respectively, 20 years and 8 years earlier. DNA mismatch repair protein expression studies disclosed loss of nuclear immunostaining of MSH6 protein, pointing to the possibility of an underlying rare MSH6 variant of the Muir-Torre syndrome, not yet described in the ophthalmic literature. p16 nuclear positivity was also found in the tumor cells, indicating the possible role of high-risk human papillomavirus as an additional factor in the genesis of the tumor. Genetic evaluation of normal and tumoral tissues in future similar cases will detect if there is an underlying germline mutation versus a somatic mutation limited to the tumor. This will be required to fully establish a predictable linkage with this new subtype of the Muir-Torre syndrome.

Muir-Torre Syndrome: The Importance of a Detailed Family History

Muir-Torre syndrome, a variant of Lynch syndrome or hereditary nonpolyposis colorectal cancer, is an autosomal dominant disease characterized by skin neoplasms (sebaceous or keratoacanthomas) and visceral malignancies. Due to the rarity of the syndrome there are no firm guidelines on how and when to test patients with its typical skin lesions. We describe a case that highlights the importance of a detailed family history.

Muir-Torre Syndrome: A Case Report in a Woman Without Personal Cancer History

We report a case of a 68-year-old white woman presenting with 5 sebaceous neoplasms, ranging from sebaceous adenoma to sebaceoma on histopathology. Despite the lack of a personal cancer history, her multiple sebaceous neoplasms and a paternal history of colon cancer prompted testing her sebaceous adenomas for microsatellite instability (MSI) by immunohistochemistry. The results showed retained nuclear expressions of MLH1 and PMS2 while MSH2 and MSH6 proteins were absent. The tumor infiltrating lymphocytes expressed both MSH2 and MSH6, providing reliable internal positive controls. Having a high probability for MSI, she was found to be heterozygous for a germline point mutation in MSH2 gene, where a pathologic variant, c.1165C > T (p.Arg389*), determined by sequencing confirmed Muir-Torre syndrome (MTS). On further genetic counseling recommendations, one of her 2 sons was found to have colon cancer in the context of his MTS. In this article, we highlight and review the implications of MSI testing by both immunohistochemistry and sequencing as they relate to confirming the diagnosis of a suspected case of MTS.

Inherited skin tumour syndromes

This article provides an overview of selected genetic skin conditions where multiple inherited cutaneous tumours are a central feature. Skin tumours that arise from skin structures such as hair, sweat glands and sebaceous glands are called skin appendage tumours. These tumours are uncommon, but can have important implications for patient care. Certain appendageal tumours, particularly when multiple lesions are seen, may indicate an underlying genetic condition. These tumours may not display clinical features that allow a secure diagnosis to be made, necessitating biopsy and dermatopathological assessment. Coupled with robust clinical assessment, biopsy findings can guide genetic testing as, increasingly, the causative genes are known for these conditions. Here we review illustrative examples of appendageal tumours and relevant advances made in genetic discovery, and suggest when referral to a geneticist may need to be considered.

Immunogenomic Classification of Colorectal Cancer and Therapeutic Implications

The immune system has a substantial effect on colorectal cancer (CRC) progression. Additionally, the response to immunotherapeutics and conventional treatment options (e.g., chemotherapy, radiotherapy and targeted therapies) is influenced by the immune system. The molecular characterization of colorectal cancer (CRC) has led to the identification of favorable and unfavorable immunological attributes linked to clinical outcome. With the definition of consensus molecular subtypes (CMSs) based on transcriptomic profiles, multiple characteristics have been proposed to be responsible for the development of the tumor immune microenvironment and corresponding mechanisms of immune escape. In this review, a detailed description of proposed immune phenotypes as well as their interaction with different therapeutic modalities will be provided. Finally, possible strategies to shift the CRC immune phenotype towards a reactive, anti-tumor orientation are proposed per CMS.

Sebaceous Neoplasms

Sebaceous skin tumors are classified into sebaceous adenoma, sebaceoma, and sebaceous carcinoma. An additional group of cystic sebaceous tumors indicate the Muir-Torre syndrome (MTS). Cystic sebaceous tumors are considered as morphologic variants of the 3 main categories. Multilineage adnexal tumors with partly sebaceous differentiation may pose a challenge to categorize. Sebaceous hyperplasia and nevus sebaceus are not considered as true sebaceous tumor entities. Recently, attention has been drawn to morphologic clues of sebaceous differentiation. Immunohistochemistry using the mismatch repair proteins and/or genetic microsatellite instability testing should be performed on sebaceous neoplasms to diagnose MTS as early as possible.

Next-generation sequencing identifies high frequency of mutations in potentially clinically actionable genes in sebaceous carcinoma

Sebaceous carcinoma (SC) is a rare but aggressive malignancy with frequent recurrence and metastases. Surgery is the mainstay of therapy, but effective systemic therapies are lacking because the molecular alterations driving SC remain poorly understood. To identify these, we performed whole-exome next-generation sequencing of 409 cancer-associated genes on 27 SCs (18 primary/locally recurrent ocular, 5 paired metastatic ocular, and 4 primary extraocular) from 20 patients. In ocular SC, we identified 139 non-synonymous somatic mutations (median/lesion 3; range 0-23). Twenty-five of 139 mutations (18%) occurred in potentially clinically actionable genes in 6 of 16 patients. The most common mutations were mutations in TP53 (n = 9), RB1 (n = 6), PIK3CA (n = 2), PTEN (n = 2), ERBB2 (n = 2), and NF1 (n = 2). TP53 and RB1 mutations were restricted to ocular SC and correlated with aberrant TP53 and RB protein expression. Systematic pathway analyses demonstrated convergence of these mutations to activation of the PI3K signalling cascade, and PI3K pathway activation was confirmed in tumours with PTEN and/or PIK3CA mutations. Considerable inter-tumoural heterogeneity was observed between paired primary and metastatic ocular SCs. In primary extraocular SC, we identified 77 non-synonymous somatic mutations (median/lesion 22.5; range 3-29). This overall higher mutational load was attributed to a microsatellite instability phenotype in three of four patients and somatically acquired mutations in mismatch repair genes in two of four patients. Eighteen of 77 mutations (23%) were in potentially clinically actionable genes in three of four patients, including BTK, FGFR2, PDGFRB, HRAS, and NF1 mutations. Identification of potentially clinically actionable mutations in 9 of 20 SC patients (45%) underscores the importance of next-generation sequencing to expand the spectrum of genotype-matched targeted therapies. Frequent activation of PI3K signalling pathways provides a strong rationale for application of mTOR inhibitors in the management of this disease. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

MSH6, Past and Present and Muir-Torre Syndrome-Connecting the Dots

Sebaceous neoplasms such as adenoma, sebaceoma, and carcinoma, although sporadic in their occurrence, are clinically significant because of their association with Muir-Torre syndrome (MTS). MTS is a rare autosomal dominant genodermatosis characterized by the occurrence of sebaceous neoplasms and/or keratoacanthomas and visceral malignancies. MTS is usually the result of germline mutations in the DNA mismatch repair genes MSH2 and, albeit less commonly, MLH1. Although less know, MSH6 is yet another key player. Evidence from Lynch syndrome indicates that pathogenic germline mutations in MSH6 are typically microsatellite stable and have a clinical presentation that differs from that associated with germline mutations in MSH2 and/or MLH1. Given this unique mutator phenotype of MSH6, the primary aim of this review was to underscore the clinical manifestations associated with pathogenic mutations in MSH6 in patients with MTS. As the current clinical and laboratory work-up of MTS is geared toward patients harboring a germline mutation in MSH2 and/or MLH1, an additional aim was to provide a scaffolding for the work-up of a patient presenting with an isolated germline mutation in MSH6.

Sebaceous Carcinoma Treated With Mohs Micrographic Surgery

BACKGROUND

Sebaceous carcinoma is a rare and potentially aggressive adnexal neoplasm with historic data indicating high rates of recurrence, metastasis, and cancer-specific mortality.

OBJECTIVE

To evaluate the incidence of local recurrence, metastasis, disease-specific mortality, and all-cause mortality and to identify work-up approaches.

PATIENTS AND METHODS/MATERIALS

Retrospective review of patients with sebaceous carcinoma treated with Mohs micrographic surgery between 2001 and 2013 at one institution.

RESULTS

Thirty-seven patients had 45 sebaceous carcinomas located on the periocular region (13%), non-periocular face (47%), scalp (7%), neck (4%), trunk (9%), and extremities (20%). The mean age was 66.1 years, and 24 (65%) patients were male. Five patients had Muir-Torre syndrome (MTS) or Lynch syndrome. Seven of 12 tumors showed loss of expression of ≥1 mismatch repair gene. The most common work-up involved taking a detailed personal and family medical history. No local recurrences, metastases, or disease-specific deaths occurred during an average follow-up of 3.6 years.

CONCLUSION

Mohs micrographic surgery is an effective treatment for sebaceous carcinoma. Detailed history taking, age-appropriate cancer screening, and immunohistochemical staining with MLH1, MSH2, or MSH6 is helpful in identifying which patients should be referred to a geneticist for work-up of MTS.

Muir-Torre syndrome (MTS): An update and approach to diagnosis and management

Muir-Torre syndrome (MTS) is a rare genetic condition that predisposes individuals to skin tumors and visceral malignancies. Because of the potentially aggressive nature of internal malignancies and sebaceous carcinoma, and the tendency to have multiple low-grade visceral cancers, close cancer surveillance is required in individuals and their families with this usually autosomal dominant disorder. Although the majority of MTS is caused by mutations in DNA mismatch repair genes resulting in microsatellite instability, a newly described subtype of MTS does not demonstrate microsatellite instability and may be inherited in an autosomal recessive pattern. In addition, MTS may be unmasked in transplant recipients taking specific immunosuppressant drugs or other immunosuppressed patients. Neoplasms may be subject to immunohistochemistry or both immunohistochemistry and genetic testing to confirm the diagnosis of MTS. Here, we offer an update and an approach to the diagnosis and management of MTS with a particular emphasis on the role of immunohistochemistry and genetic testing.

Updates on the Molecular Pathology of Selected Ocular and Ocular Adnexal Tumors: Potential Targets for Future Therapy

Ophthalmic pathologic studies of retinoblastoma first definitively elucidated a genetic etiology for cancer three decades ago. Advances in DNA sequencing, protein expression profiling, and the exploration of epigenetics have since led to categorization of tumors and clinical prognostication based on genetic aberrancy. There are now many neoplasms that are defined by a characteristic genetic signature. In the past several years alone, much has been discovered in regard to the original tumor-suppressor gene initially defined in retinoblastoma as well as in other intraocular tumors such as medulloepithelioma. Our further understanding of ocular adnexal tumors that result in substantial morbidity and mortality, such as sebaceous carcinoma, has also benefited from a genetic approach. In this article, we review the clinicopathologic features of the foregoing three entities--retinoblastoma, medulloepithelioma, and sebaceous carcinoma--in order to highlight discoveries in their underlying abnormal molecular genetic functioning.

Muir-Torre Syndrome Presenting as Sebaceous Adenocarcinoma and Invasive MSH6-Positive Colorectal Adenocarcinoma

Muir-Torre syndrome (MTS) is a rare genodermatosis, diagnosed by the presence of sebaceous neoplasms along with an internal malignancy, most commonly colorectal carcinomas. MTS is most commonly caused by microsatellite instabilities of the hMLH1 and hMSH2 mismatch repair genes, and is rarely caused by mutations of the hMSH6 gene. We describe the case of a 56-year-old male who presented with an enlarging mass on his back as well as hematochezia. The back mass was excised, and pathology confirmed microsatellite instability in MSH2 and MSH6. Abdominal CT and colonoscopy confirmed the presence of synchronous masses in the cecum, ascending colon, and the transverse colon. He refused any further workup or treatment, only to return 8 months later complaining of hematochezia and discomfort due to an enlarging mass protruding from the rectum. After consenting to surgical intervention, he agreed to outpatient chemotherapy treatment. The presence of sebaceous neoplasms should raise suspicion for the possibility of an associated internal malignancy.

Generational Expression of Muir-Torre Syndrome in a Canadian Family

Muir-Torre syndrome (MTS) is a rare autosomal dominant inherited genodermatosis that is considered to be a phenotypic subtype of hereditary nonpolyposis colorectal cancer (HNPCC), commonly referred to as Lynch syndrome. We describe the clinical course of a 57-year-old female patient with MTS. She has a confirmed HMSH2 mutation. Recently she presented with two nodular lesions. Histologic examination confirmed these lesions to be sebaceous neoplasms. The patient has a history of endometrial and colorectal adenocarcinoma as well as several nonspecific sebaceous lesions throughout her life. She has a confirmed extensive family history of MTS with both male and female family members harbouring either HMLH1 or HSMH2 mutations. Affected relatives have presented at different ages throughout their lives with cutaneous neoplasms and visceral malignancies, including malignancies rarely associated with MTS. MTS presents a diagnostic challenge for clinicians. The case demonstrates that the management of MTS, a potentially underreported syndrome, requires a multiprofessional approach incorporating vigilance, screening, and expert knowledge for successful diagnosis and potentially improved prognosis for patients and their families. The case also demonstrates the varied heritability of MTS and prompts the question of how MTS is expressed in succeeding generations.

Importance of universal mismatch repair protein immunohistochemistry in patients with sebaceous neoplasia as an initial screening tool for Muir-Torre syndrome

Muir-Torre syndrome, a Lynch syndrome variant, is characterized by sebaceous neoplasia plus one or more malignancies, typically colon cancer. The significance of DNA mismatch repair (MMR) deficiency detection by immunohistochemistry (IHC) in colorectal carcinomas is well established and is recommended as a screening tool for Lynch syndrome in newly diagnosed colorectal carcinomas. In comparison, literature on IHC application to detect MMR proteins (MLH1, MSH2, MSH6, and PMS2) in sebaceous neoplasia has been less studied and has been derived almost exclusively from tertiary care centers. Herein we describe the largest series to date characterizing MMR deficiency in sebaceous neoplasms, as well as the relative frequencies of each deficiency. Two hundred sixteen consecutive sebaceous neoplasms (216 patients) were analyzed from a community practice setting (133 sebaceous adenomas, 68 sebaceomas, 15 sebaceous carcinomas). One hundred forty-three were MMR deficient (66%), of which 90 were MSH2/MSH6 deficient (63%), 27 MLH1/PMS2 deficient (19%), 22 MSH6 deficient (15%), and 4 PMS2 deficient (3%). MMR deficiency was significantly associated with site, with tumors off of the head and neck more likely to be MMR deficient (specificity 96%). In contrast to prior reports, no significant trend in MMR-deficient versus -nondeficient tumors was seen in age at presentation (median age, 68 versus 66), tumor-infiltrating lymphocytes, or tumor type. Given the low sensitivity of age < 60 years (30%), location off of the head and neck (41%), or presence of tumor-infiltrating lymphocytes (29%) in MMR deficiency detection, IHC screening programs should test all sebaceous neoplasms for MMR deficiency, regardless of their clinicopathological features.

Multiple apocrine poromas: a new case report

Apocrine poromas are rare and distinctive benign adnexal neoplasms featuring tumor cells differentiating toward folliculosebaceous-apocrine units. We report an extremely rare case with multiple apocrine poromas in a single patient. Fifteen tumors were distributed on the head, neck, forearm and axilla of a 74-year-old man. All tumors were mostly composed of poroid cells that surrounded variably sized duct spaces, some of which exhibited decapitation secretion. The poroid cells were continuous with infundibulum-like structures that contained aggregates of mature sebocytes. The patient had no family history of similar tumors and no history of immunosuppressive therapy. This is the first report of multiple apocrine poromas, suggesting that predisposing genetic factors might play a part in the development of the tumors.

Hereditary Syndromes Manifesting as Endometrial Carcinoma: How Can Pathological Features Aid Risk Assessment?

Endometrial carcinoma is the most common gynecological tumor worldwide. It can be the presenting malignancy, acting as the harbinger, of an undiagnosed hereditary syndrome. Up to 50% of females with Lynch syndrome present in this manner. Differentiation between Lynch, Muir-Torre, and Cowden syndromes can at times be challenging due to the overlapping features. Our review emphasizes on the strengths, pitfalls, and limitations of microscopic features as well as immunohistochemical and polymerase chain reaction- (PCR-) based tests used by laboratories to screen for DNA mismatch repair (MMR) and PTEN gene mutations in patients to enable a more targeted and cost effective approach in the use of confirmatory gene mutational analysis tests. This is crucial towards initiating timely and appropriate surveillance measures for the patient and affected family members. We also review the evidence postulating on the possible inclusion of uterine serous carcinoma as part of the spectrum of malignancies seen in hereditary breast and ovarian carcinoma syndrome, driven by mutations in BRCA1/2.

Immunohistochemistry in dermatopathology

CONTEXT

Immunohistochemistry is not a diagnostic test but a highly valuable tool that requires interpretation within a context.

OBJECTIVE

To review the current status and limitations of immunohistochemistry in dermatopathology.

DATA SOURCES

English-language literature published between 1980 and 2014.

CONCLUSIONS

Although immunohistochemistry is rarely completely specific or sensitive, it is an important adjunctive technique in dermatopathology and can be helpful in a series of diagnostic dilemmas.

Sebaceous carcinoma: review of the literature

BACKGROUND

Sebaceous carcinoma is an uncommon adnexal neoplasm with a documented capability for regional and distant metastasis. Traditionally, sebaceous carcinoma has been associated with high rates of recurrence after excision.

OBJECTIVE

To review the current literature on sebaceous carcinoma and detail its epidemiology, pathogenesis, clinical presentation, histopathology, diagnostic workup, treatment, and prognosis.

MATERIALS AND METHODS

Literature review using PubMed search for articles related to sebaceous carcinoma.

RESULTS

Sebaceous carcinoma typically presents as a painless pink or yellow nodule. Diagnosis requires histopathologic examination, and immunohistochemical analysis often assists in the differentiation of sebaceous carcinoma from other benign and malignant skin neoplasms. Sebaceous carcinoma should prompt a workup for Muir-Torre syndrome. Periorbital sebaceous carcinoma has an increased tendency for regional metastasis, although cancer-specific mortality rates are similar among all anatomic locations.

CONCLUSION

Surgery is the preferred treatment for local disease. Limited data suggest that Mohs micrographic surgery may provide superior clinical outcomes, but more research is needed regarding the long-term outcomes. Radiation and systemic chemotherapy are reserved for recurrent or metastatic disease.

Sebaceous neoplasms and the immunoprofile of mismatch-repair proteins as a screening target for syndromic cases

INTRODUCTION

Muir-Torre syndrome (MTS), a subset of Lynch syndrome, is characterized by concurrent or sequential development of sebaceous neoplasms, and internal malignancies, specifically colorectal carcinoma (CRC), and can be related to mismatch-repair (MMR)-protein deficiency. In CRC context, p16-negativity in MLH1-deficient cases may denote methylation rather than mutation. The prime aim of this study was to evaluate the mismatch-repair (MMR)-protein deficiency and the p16 status among sebaceous neoplasms.

MATERIAL AND METHOD

From January 1990 through October 2012, 26 sebaceous adenomas (SAs) and 6 sebaceous carcinomas (SCs) were accrued. The expression of MLH1, MSH2, MSH6, and PMS2 was recorded. MLH1-deficient cases were tested for p16 status.

RESULTS

Eighteen (56%) of the 32 specimens with SA or SC displayed MMR-protein deficiency, comprising 17 (65.4%) SAs (MSH2/MSH6 loss in 12, MLH1/PMS2 loss in 3, MSH6 loss only in 2 cases) and 1 (16.7%) SC (MLH1/PMS2 loss). All 4 MLH1 deficient cases were p16-positive.

CONCLUSION

A substantial proportion of sebaceous neoplasms were MMR-protein deficient and thus likely MTS candidates. Given the low prevalence of sebaceous neoplasms in Denmark, immunohistochemistry for the four MMR-proteins is recommended in the initial diagnostic approach. The addition of p16 was none-informative, but evaluation of its utility in larger series is warranted.

The genetic basis of Lynch syndrome and its implications for clinical practice and risk management

Lynch syndrome is the most common cause of hereditary colon cancer, and accounts for as much as 3% of all colon and endometrial cancers. The identification and management of individuals with Lynch syndrome have evolved over the past 20 years, yet the syndrome remains vastly underdiagnosed. It is important for clinicians to recognize individuals and families who are at risk in order to be able to manage them appropriately and reduce their morbidity and mortality from this condition. This review will touch on the history of Lynch syndrome, the current knowledge of genotype–phenotype correlations, the cancers associated with Lynch syndrome, and management of individuals who are gene carriers.

[Genodermatoses with malignant skin tumors]

Cutaneous malignancies can manifest as isolated and sporadic tumors as well as multiple and disseminated tumors. In the latter case they often point to a genetic disease, which either can be restricted to the skin exclusively or also involve extracutaneous organs in the context of a hereditary tumor syndrome. Such hereditary tumor syndromes are clinically and genetically very heterogeneous. Therefore, the prevailing specific skin tumors play an important diagnostic role in the case of complex symptom constellations. Elucidation of the genetic basis of rare monogenetically inherited disorders and syndromes can contribute to a better understanding of the pathogenesis of frequently occurring cutaneous malignancies because the mutated genes often encode proteins, which have a key position in metabolic signaling pathways that are of high significance for the development of targeted therapies. Here we provide an overview of genodermatoses, which are associated with basal cell carcinomas, sebaceous carcinomas, keratoacanthomas, squamous cell carcinomas and malignant melanomas.

CRB1: one gene, many phenotypes

Mutations in the CRB1 gene cause severe retinal degenerations, which may present as Leber congenital amaurosis, early onset retinal dystrophy, retinitis pigmentosa, or cone-rod dystrophy. Some clinical features should alert the ophthalmologist to the possibility of CRB1 disease. These features are nummular pigmentation of the retina, atrophic macula, retinal degeneration associated with Coats disease, and a unique form of retinitis pigmentosa named para-arteriolar preservation of the retinal pigment epithelium (PPRPE). Retinal degenerations associated with nanophthalmos and hyperopia, or with keratoconus, can serve as further clinical cues to mutations in CRB1. Despite this, no clear genotype-phenotype relationship has been established in CRB1 disease. In CRB1-disease, as in other inherited retinal degenerations (IRDs), it is essential to diagnose the specific disease-causing gene for the disease as genetic therapy has progressed considerably in the last few years and might be applicable.

Hypermethylation of the CDKN2A gene promoter is a frequent epigenetic change in periocular sebaceous carcinoma and is associated with younger patient age

Periocular sebaceous carcinoma is an aggressive neoplasm with significant morbidity and mortality. Its pathogenesis is poorly understood. It is only rarely associated with Muir-Torre syndrome. Previous studies from Asian countries, have suggested that human papillomavirus (HPV) infection plays a role in the pathogenesis and overexpression of p16(INK4a), a surrogate marker of HPV infection, have also been reported. However, data from western countries seem contradictory. In order to clarify and explore the molecular and epigenetic basis of HPV, CDKN2A status and role of microsatellite instability in the development of periocular sebaceous carcinoma, 24 cases of periocular sebaceous carcinoma were analyzed for the expression of p16(INK4a) and mismatch repair proteins (MLH1, MSH2, MSH6 and PMS2) via immunohistochemistry. Nested polymerase chain reaction (PCR) and genechip HPV typing were used to detect HPV infection and decide its genotype when present. PCR amplification using a consensus primer pair was also performed to detect β-HPV. The methylation status of CDKN2A promoter region was studied by methylation-specific polymerase chain reaction. HPV-positivity was demonstrated in only one of our cases (HPV 16), while another case showed p16(INK4a) overexpression. All cases showed preserved expression of mismatch repair proteins. CDKN2A promoter hypermethylation was noted in nearly half of our cases (11/24) and was associated with younger patient age (P = .013). Our results showed that periocular sebaceous carcinoma is rarely associated with HPV and microsatellite instability. Higher frequency of CDKN2A promoter hypermethylation in younger patients implies a significant epigenetic role in tumor development in this age group.

Mismatch repair protein deficiency is common in sebaceous neoplasms and suggests the importance of screening for Lynch syndrome

The association between Lynch syndrome and sebaceous neoplasms is well characterized. The absence of expression of mismatch repair proteins (MMRPs) by immunohistochemistry (IHC) is often used in other Lynch-associated tumors to guide testing. IHC for MLH1, PMS2, MSH2, and MSH6 was performed on 36 benign and malignant sebaceous neoplasms with the absence of one or more MMRP in 38.9% of cases. Among lesions with abnormal IHC, 71.4% were missing both MSH2 and MSH6, 21.4% lacked MLH1 and PMS2, and 7.1% lacked only MSH6. Of the 10 patients with absent MMRP, 5 had gene-test confirmed Lynch syndrome, 3 had no suggestive personal or family medical history and 2 had no recorded data. Tumor-infiltrating lymphocytes in neoplasms with absent MMRP were statistically significantly greater than in those with intact MMRP (16.5 vs. 9.7, P = 0.027). MMRP deficiency is common in sebaceous neoplasms, suggesting the importance of screening for Lynch syndrome in these patients.

What is new in adnexal tumors of the skin?

This article reviews the recent dermatopathology literature regarding cutaneous adnexal neoplasms, with emphasis on new and underrecognized entities, "old entities" with new findings, advances in immunohistochemistry, and new findings in relation to inherited disorders associated with cutaneous adnexal neoplasms.

The skin: a mirror to the gut

INTRODUCTION

This review discusses the diseases with involvement of both skin and gut. GI manifestations of vesicobullous disorders and systemic diseases and syndromes involving skin and gut, dermatologic manifestations of inflammatory bowel disease (IBD), polyposis syndromes, and GI malignancies have been discussed. Diagnostic and treatment approaches towards these disorders are summarized.

CONCLUSIONS

Interaction of the skin and gut has always been an area of inquisitiveness. Gastrointestinal (GI) tract can be involved in dermatological disorders or GI diseases can have a dermatological manifestation.

A case of Muir-Torre syndrome with multiple cancers of bilateral eyelids and breast

We report a case of Muir-Torre syndrome (MTS) with a very rare combination of cancers, involving bilateral eyelid cancers and breast cancer. A 71-year-old female with a history of breast cancer from 18 years prior presented with bilateral eyelid tumors. One of her siblings had lung cancer, and another had pancreatic cancer. She underwent excisional biopsy of the eyelid tumors and histopathology revealed sebaceous carcinoma of the right eyelid and basal cell carcinoma of the left. She was diagnosed with MTS: a skin cancer associated with visceral malignancy. Immunohistochemical tests for mutS homolog 2 showed a lack of expression in both eyelid carcinomas.