S1-Guideline Sebaceous Carcinoma

Sebaceous gland carcinomas are rare malignant cutaneous adnexal tumors with sebocytic differentiation. The typical predilection area is the head and neck region, where sebaceous gland carcinomas are the most common malignant adnexal tumors of the skin. According to their localization a distinction is made between periocular and extraocular sebaceous gland carcinomas. Muir-Torre syndrome (MTS) should always be ruled out if it is suspected. In terms of prognosis, sebaceous gland carcinomas are potentially aggressive tumors with a clear tendency to recur and metastasize. Only small extraocular sebaceous gland carcinomas that have been completely resected have a very good prognosis. Sebaceous gland carcinomas most frequently metastasize lymphogenously to regional or distant lymph nodes; organ metastasis occurs less frequently. Periocular sebaceous gland carcinomas have a higher metastasis rate (up to 15%) than extraocular sebaceous gland carcinomas (up to 2%). Complete micrographically controlled surgery (MCS) of the primary tumor is the therapy of first choice, regardless of periocular or extraocular localization. Adjuvant or therapeutic radiotherapy may be considered. There is currently no established standard therapy for advanced, inoperable, or metastatic sebaceous gland carcinomas. Local procedures and systemic therapies such as chemotherapy or immunotherapy can be considered. The procedure should be determined individually by an interdisciplinary tumor board. Close follow-up care is recommended for these potentially aggressive carcinomas.

Mosaic Muir Torre Syndrome: Keratoacanthoma as a Piece of the Puzzle

ABSTRACT

Lynch syndrome is an inherited condition, which increases the risk of numerous visceral malignancies and cutaneous tumors such as keratoacanthomas and sebaceous tumors. It is typically identified by immunohistochemistry of tissue taken from tumors or through genetic testing with next-generation sequencing. Diagnosing Lynch syndrome becomes more complex when the individual is mosaic for the relevant pathogenic variant. There are very few cases of this reported in the medical literature. It is even more unusual for the diagnosis to be made based on testing of a keratoacanthoma lesion. We report a case where immunohistochemistry of a keratoacanthoma helped make a diagnosis of mosaic Lynch syndrome. We will explore how mosaicism should be considered when a phenotype is strong, even if next-generation sequencing reports no pathogenic or likely pathogenic variant and how lesions such as keratoacanthomas can have a role in the early detection and treatment of future malignancies.

Muir-Torre syndrome and recent updates on screening guidelines: The link between colorectal tumors and sebaceous adenomas in unusual locations

BACKGROUND

Muir-Torre syndrome (MTS) is a rare genetic disorder that is caused by mismatch repair (MMR) protein mutations. MTS increases the risk of developing skin and gastrointestinal tumors such as sebaceous adenomas (SAs), sebaceous carcinomas, colorectal cancer, endometrial cancer, and ovarian cancer. The risk of developing these types of tumors varies depending on the involved mutation and the individual's family history risk.

CASE PRESENTATION

A 47-year-old male presented with multiple skin lesions on the scalp, face, flank, and back. The examination revealed well-circumscribed, dome-shaped papules with a yellowish appearance with white oily material in the center. Histopathologic examination showed a well-circumscribed sebaceous neoplasm consistent with a mixture of basaloid cells and lobules of bland-appearing mature adipocytes that communicate directly to the surface epithelium. Focal cystic changes and peritumoral lymphocytic infiltrate were noted. Increased mitotic figures were seen in the basaloid cell component. The overall findings were consistent with the diagnosis of SAs. MMR staining showed preserved expression in MLH1 and PMS2 proteins, while MSH2 and MSH6 staining showed loss of protein expression. A screening colonoscopy showed numerous colon and rectal tumors, prompting concerns about the likelihood of MTS. Surgical intervention was pursued for complete resection. Histology revealed a diagnosis of mucinous adenocarcinoma/adenocarcinoma with mucinous features of the colon. The diagnosis of MTS was supported by molecular testing that revealed MSH2 germline mutation. The increased likelihood of MTS was attributed to the occurrence of SAs in unusual locations of the head and neck regions, unlike typical cases.

CONCLUSION

MTS is a rare clinical condition that necessitates prompt thorough evaluation and periodic surveillance. When SA is encountered in atypical locations, it is important to consider additional testing supported by immunohistochemical staining, molecular testing, and regular screening to exclude the likelihood of MTS.

Muir-Torre Syndrome with Novel Mutation in the MSH2 Gene

Muir-Torre syndrome (MST) is a rare autosomal dominant subtype of hereditary non-polyposis colorectal carcinoma. The diagnosis is established based on the coexistence of sebaceous gland tumors and visceral organ malignancies. Mutations in the mismatch repair genes are responsible for Muir-Torre syndrome. Internal malignancies seen in MTS are most commonly colorectal, gastrointestinal system, endometrial, genitourinary system, breast, lung, brain, and hepatobiliary system malignancies. Detection of sebaceous neoplasia is essential in investigating Muir-Torre syndrome, allowing early detection of internal malignancies. Herein, we present the case of a patient with sebaceous adenomas, internal malignancies, and a new mutation detected during the genetic examination.

Sebaceous carcinoma epidemiology, associated malignancies and Lynch/Muir-Torre syndrome screening in England from 2008 to 2018

BACKGROUND

Sebaceous carcinomas (SC) may be associated with the cancer predisposition syndrome Muir-Torre/Lynch syndrome (MTS/LS), identifiable by SC mismatch repair (MMR) screening; however, there is limited data on MMR status of SC.

OBJECTIVE

To describe the epidemiology of SC, copresentation of other cancers, and population level frequency of MMR screening in SC.

METHODS

A population-based retrospective cohort study of SC patients in the National Cancer Registration and Analysis Service in England.

RESULTS

This study included 1077 SC cases (739 extraocular, 338 periocular). Age-standardized incidence rates (ASIR) were higher in men compared with women, 2.74 (95% CI, 2.52-9.69) per 1,000,000 person-years for men versus 1.47 person-years (95% CI, 1.4-1.62) for women. Of the patients, 19% (210/1077) developed at least one MTS/LS-associated malignancy. MMR immunohistochemical screening was performed in only 20% (220/1077) of SC tumors; of these, 32% (70/219) of tumors were MMR deficient.

LIMITATIONS

Retrospective design.

CONCLUSIONS

Incorporation of MMR screening into clinical practice guidelines for the management of SC will increase the opportunity for MTS/LS diagnoses, with implications for cancer surveillance, chemoprevention with aspirin, and immunotherapy treatment targeted to MTS/LS cancers.

Immunohistochemistry, Molecular Biology, and Clinical Scoring for the Detection of Muir-Torre Syndrome in Cutaneous Sebaceous Tumors: Which Strategy?

BACKGROUND

Sebaceous neoplasms (SNs) always raise the possibility of an association with Muir-Torre syndrome (MTS) and permit to screen internal malignancies, colorectal and endometrial carcinomas, before they become symptomatic. Immunohistochemistry (IHC), molecular biology, and clinical examination are different approaches for detection of MTS. We conducted a retrospective analysis of non-selected SNs in order to determine the optimal tools to implement for MTS screening.

METHODS

Deficient MMR phenotype (dMMR) was determined by either IHC using antibodies directed to four mismatch repair (MMR) antigens on tissue microarray or molecular biology using pentaplex PCR. The Mayo Clinic risk score of MTS was calculated from medical records. Sensibility and specificity of each test for the detection of MTS were determined.

RESULTS

We included 107 patients, 8 with multiple SNs, for a total of 123 SNs (43 sebaceous adenomas, 19 sebaceomas, and 61 sebaceous carcinomas (SC)). Loss of at least one MMR protein was observed in 70.7% of tumors, while 48% had a microsatellite instable phenotype. Concordance between both techniques was 92.9%, with a 0.85 Cohen's kappa coefficient. Nineteen patients (20.2%) had a ≥2 points Mayo Clinic risk score, one having a pMMR SC. Among the 13 patients with confirmed MTS, 2 had a low Mayo Clinic risk score (1 point). IHC had the highest sensitivity for MTS screening (100%) with a specificity of 34.1%, while a >2-point Mayo Clinic risk score had a lower sensitivity (92%) but a higher specificity (89%).

CONCLUSION

To detect MTS in SN patients, the first-line Mayo Clinic risk score followed by IHC appears to be the most accurate strategy with lower cost for society. This strategy should be adapted to the medico-economic resources of each country.

Seborrheic Keratosis With Sebaceous Differentiation, a Series of 8 Cases and Critical Review of the Literature

ABSTRACT

Seborrheic keratosis with sebaceous differentiation (SKSD) can sometimes raise uncertainty, confuse with other even malignant entities, and lead to overestimation of this harmless variant. Retrospective analysis of the cases diagnosed as SKSD and a search of the pertaining literature were conducted. Eight cases of SKSD were found. Histologically, these lesions show a flat to plate-like outgrowth of basaloid cells with solitary or clustered sebocytes at the bottom of the rete ridges and variable sebaceous ducts with luminal cuticula. The lesions differed in the outgrowth subpattern: flat/macular, acanthotic, or reticulated. No association was found with Muir-Torre syndrome, and no malignant transformation was seen in these lesions. Literature search revealed confusingly designated lesions that simply represented SKSD. SKSD can show several growth patterns as classic SK. This entity is either underreported or even underrecognized. This entity is benign; however, according to the literature, exclusion of an associating Muir-Torre syndrome should be warranted. The published literature about this lesion is confusing and inconsistent. We suggest the avoidance of confusing terminology and particularly the terminus epithelioma for such lesions.

Muir-Torre Syndrome

A 64-year-old man was referred to our dermatology clinic with a diagnosis of Muir-Torre syndrome (MTS), he had a history of multiple sebaceous carcinomas and sebaceous adenomas removed over the years. The patient has also had visceral cancer and had undergone a colon resection 17 years before to treat colon cancer and was recently diagnosed with invasive high-grade urothelial carcinoma of the right ureter. In addition, the patient has an extensive family history of cancer; a pedigree was constructed to document this history (Figure 1). Of note is that the patient's mother and father were second cousins. The patient's father was diagnosed with lung cancer at age 57 and died of colon cancer at the age of 72. The patient's mother died of colon cancer at age 74. The patient has three siblings: a sister and two brothers. The sister died of bone cancer at age 42. One brother had a number of cancers including colon, kidney, and skin cancers and died at age 53. His other brother is alive and has a history of colon cancer, kidney cancer, and ureteral cancer. The patient has five children. He has a 40-year-old son who, at the age of 30, was diagnosed with testicular cancer. His daughters are 47, 44, 39, and 34, with no history of malignancy to date. The patient had three maternal aunts, all of whom succumbed to colon cancer, as well as two paternal uncles who died of lung cancer. The patient's maternal grandfather was a smoker and he also died of lung cancer.

The DNA mismatch repair system in sebaceous tumors: an update on the genetics and workup of Muir-Torre syndrome

Mutations in the genes encoding the DNA mismatch repair (MMR) are identified in most sebaceous neoplasms. Sebaceous tumors are rare in the general population; however, they are common in patients with inherited or acquired mutations in the MMR system. This article describes the DNA MMR system and its implication in sebaceous tumors as well as discusses the recent recommendations for screening for Muir-Torre syndrome (MTS) in patients presenting with sebaceous tumors.

[Muir-Torre syndrome]

Muir-Torre syndrome (MTS) is an autosomal dominant disease with approximately 200 reported cases worldwide, which is characterised by multiple neoplasms of the skin and internal organs. This is a case report of a 57-year-old woman with MTS, who was referred to a plastic surgery department from a gastroenterology department due to a neoplasm of the skin. After treatment, she was referred to a dermatology department for follow-up. MTS is a rare disease, which is now reported in Denmark. Doctors treating any of the composing elements should have basic knowledge of the condition in order to refer patients appropriately.

Lynch Syndrome and Muir-Torre Syndrome: An update and review on the genetics, epidemiology, and management of two related disorders

Hereditary Nonpolyposis Colorectal Cancer (HNPCC), also known as Lynch Syndrome, is an autosomal dominant, tumor predisposing disorder usuallycaused by germline mutations in mismatch repair (MMR) genes. A subset of HNPCC, Muir-Torre Syndrome (MTS) also involves MMR gene defects and is generally accepted as a variant of HNPCC. MTS is typicallycharacterized by at least one visceral malignancy and one cutaneous neoplasm of sebaceous differentiation, with or without keratoacanthomas. In either version of the disorder, nonfunctional MMR systems lead tothe loss of genomic integrity, marked commonly by mismatches in repetitive DNA sequences, resulting in microsatellite instabilities. Deleterious nucleotide alterations ultimately drive the process of tumorigenesis in both HNPCC and MTS. The following article reviews the epidemiology, genetics, clinical presentation, and management of HNPCC and its MTS variant.

Analysis of Sebaceous Neoplasms for DNA Mismatch Repair Proteins in Muir-Torre Syndrome

Muir-Torre syndrome is a rare genodermatosis inherited most frequently in an autosomal dominant fashion. Current criteria for its diagnosis include at least one sebaceous tumor and an underlying visceral malignancy. Muir-Torre syndrome is strongly associated with a germline mutation in DNA mismatch repair genes. We report two patients with a history of colorectal carcinoma who presented with sebaceous neoplasms on the face and trunk. Immunohistochemical staining of the sebaceous neoplasms demonstrated absence of mismatch repair proteins MSH2 and MSH6. Genetic studies confirmed deletions in the MSH2 gene, and a diagnosis of Lynch syndrome was made. Immunohistochemical staining for mismatch repair genes MLH1, MSH2, MSH6 and PMS2 may aid in the diagnosis of Muir-Torre syndrome in cases where there is high suspicion. Genetic testing is an important final step in the confirmation of Muir-Torre syndrome.

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.

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.

Sebaceous adenoma arising in mature cystic teratoma of the ovary. Case report

We report the case of a 44-year-old female with sebaceous adenoma arising in mature cystic teratoma of the ovary. The patient had a tumor in the left ovary; 125 x 90 x 70 mm. Microscopically, the tumor consisted of structures typical of dermoid cysts. However, large areas of sebaceous proliferation were found. These areas were comprised of sebaceous nodules with features similar to a sebaceous adenoma of the skin. Immunohistochemically, the tumor showed "wild-type" expression of p53 and low proliferative activity (Ki-67 index < 5%). To verify the possibility of Muir-Torre syndrome we performed immunohistochemical examination of DNA mismatch repair proteins expression. However, all four proteins examined (MSH2, MSH6, MLH1, PMS2) were positive. Sebaceous adenoma arising in mature teratoma of the ovary is rare. To the best of our knowledge, only six cases have been reported in the literature to date.

[Lynch syndrome, Muir Torre variant: 2 cases]

Lynch syndrome (LS) is an autosomal-dominant inherited cancer predisposition syndrome caused by germline mutations in DNA mismatch repair genes (MLH1, MSH2, MSH6 or PMS2). Muir-Torre syndrome (MTS) is a phenotypic variant of LS that includes a predisposition to sebaceous glands tumors and keratoacanthomas. We report two patients with MTS, with more than one LS-related cancer, skin lesions, family history of cancer andmicrosatellite instability and immunohistochemistry analysis.

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.

Screening for germline mismatch repair mutations following diagnosis of sebaceous neoplasm

IMPORTANCE Sebaceous neoplasms (SNs) define the Muir-Torre syndrome variant of Lynch syndrome (LS), which is associated with increased risk for colon and other cancers necessitating earlier and more frequent screening to reduce morbidity and mortality.Immunohistochemical (IHC) staining for mismatch repair (MMR) proteins in SNs can be used to screen for LS, but data on subsequent germline genetic testing to confirm LS diagnosis are limited.OBJECTIVE To characterize the utility of IHC screening of SNs in identification of germline MMR mutations confirming LS.DESIGN, SETTING, AND PARTICIPANTS Retrospective study at 2 academic cancer centers of 86 adult patients referred for clinical genetics evaluation after diagnosis of SN.MAIN OUTCOMES AND MEASURES Results of tumor IHC testing and germline genetic testing were reviewed to determine positive predictive value and sensitivity of IHC testing in diagnosis of LS. Clinical variables, including age at diagnosis of SN, clinical diagnostic criteria for LS and Muir-Torre syndrome, and family history characteristics were compared between mutation carriers and noncarriers.RESULTS Of 86 patients with SNs, 25 (29%) had germline MMR mutations confirming LS.Among 77 patients with IHC testing on SNs, 38 (49%) had loss of staining of 1 or more MMR proteins and 14 had germline MMR mutations. Immunohistochemical analysis correctly identified 13 of 16 MMR mutation carriers, corresponding to 81% sensitivity. Ten of 12 patients(83%) with more than 1 SN had MMR mutations. Fifty-two percent of MMR mutation carriers did not meet clinical diagnostic criteria for LS, and 11 of 25 (44%) did not meet the clinical definition of Muir-Torre syndrome. CONCLUSIONS AND RELEVANCE Immunohistochemical screening of SNs is effective in identifying patients with germline MMR mutations and can be used as a first-line test when LSis suspected. Abnormal IHC results, including absence of MSH2, are not diagnostic of LS and should be interpreted cautiously in conjunction with family history and germline genetic testing. Use of family history to select patients for IHC screening has substantial limitations,suggesting that universal IHC screening of SNs merits further study. Clinical genetics evaluation is warranted for patients with abnormal IHC test results, normal IHC test results with personal or family history of other LS-associated neoplasms, and/or multiple SNs.

[Sebaceous breast carcinoma: report of a rare histological special subtype]

We report on a case of sebaceous carcinoma of the breast as a rare histological special subtype of breast cancer. Because these tumors are uncommon, differential diagnostic considerations and the exclusion of Muir-Torre syndrome are emphasized. Finally possible mechanisms of development and therapeutic strategies for this carcinoma are discussed.

Muir-Torre syndrome: case report and molecular characterization

CONTEXT

Muir-Torre syndrome is a rare autosomal dominant genodermatosis caused by mutations in the mismatch repair genes. It is characterized by the presence of sebaceous skin tumors and internal malignancies, affecting mainly the colon, rectum and urogenital tract. Awareness of this syndrome among physicians can lead to early diagnosis of these malignancies and a better prognosis.

CASE REPORT

We report the case of a Chilean patient who, over the course of several years, had multiple skin lesions, endometrial cancer and colon cancer. The syndrome was diagnosed using molecular techniques such as microsatellite instability analysis, immunohistochemistry and DNA sequencing, which allowed us to find the causative mutation.

CONCLUSION

Molecular diagnostics is a highly useful tool, since it allows clinicians to confirm the presence of mutations causing Muir-Torre syndrome. It is complementary to the analysis of the clinical data, such as dermatological presentation, presence of visceral malignancies and family history of colorectal tumors, and it provides important knowledge to help physicians and patients choose between treatment options.

Muir-Torre Syndrome / Turcot Syndrome overlap? A patient with sebaceous carcinoma, colon cancer, and a malignant astrocytoma

The Muir-Torre Syndrome is characterized by the clinical constellation of sebaceous neoplasms, keratoacanthomas, and internal malignancies caused by a defect in DNA mismatch repair. Another mismatch repair defect causes Turcot syndrome, which manifests with colorectal and central nervous system neoplasms. We wish to report a case in which the manifestations of both syndromes were observed in the same patient. We further discuss the possible genetic basis for this overlap.

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.

[Muir-Torre syndrome--a phenotypic variant of Lynch syndrome]

Muir-Torre syndrome (MTS) represents an autosomal dominantly inherited condition and is considered a phenotypic variant of the more common hereditary nonpolyposis colorectal cancer syndrome (HNPCC), or Lynch syndrome. MTS combines at least one cutaneous neoplasm with sebaceous differentiation (e.g. sebaceoma, sebaceous adenoma, and sebaceous carcinoma), and at least one visceral malignancy. MTS is a genetic disorder caused by a germline mutation in one of the DNA mismatch repair (MMR) genes. Tumors in MTS patients are characteristically associated with the loss of MMR protein expression and/or microsatellite instability (70%). Patients who are suspected to have MTS/Lynch syndrome are often identified by dermatologists, dermatopathologists/pathologists, gastroenterologists and gynecologists. If MTS is suspected on a clinicopathological ground, necessary additional laboratory investigations should be performed only in specialized pathological departments providing immunohistochemistry and molecular biologic analysis service.

Muir-Torre syndrome: Facts and controversies

The cutaneous presentation of a tumor sometimes has implications for a patient and his or her family, and Muir-Torre syndrome is an example of this. Because a single skin lesion can have broad consequences, it is important for clinicians to be aware of Muir-Torre syndrome. The definition, potential clues, the role of ancillary testing (microsatellite, immunohistochemical, and genetic), and screening recommendations are reviewed.

Immunohistochemistry screening of sebaceous lesions for Muir-Torre syndrome in a 26-year period in a Mexican population

Muir-Torre syndrome (MTS) is an autosomal dominant genodermatosis defined as the association of rare sebaceous gland skin tumors, keratoacanthomas, and a personal or familial history of malignant visceral tumors. Germline mutations in certain mismatch repair genes (MMR) have been identified in MTS families and their identification is a cornerstone for diagnosis of MTS. We reviewed our series of sebaceous neoplasms and performed immunohistochemistry (IHC) in order to screen for new MTS cases. Sebaceous neoplasms and visceral tumors from the same patient diagnosed between 1980-2006 were included. Immunohistochemistry to determine the presence or absence of MMR gene products in skin and visceral tumors was performed with mouse monoclonal antibodies anti-MSH2, anti-MSH6 and anti-MLH1. Six sebaceous neoplasms were identified in six females. Four patients presented a lack of expression of at least one of the MMR proteins in visceral and cutaneous neoplasms, thus warranting the diagnosis of MTS. Immunohistochemistry is a useful and accessible technique for the characterization of MMR gene expression in patients with sebaceous neoplasms.

[Clinical follow-up and presence of visceral tumors in 12 patients with sebaceous gland tumors]

BACKGROUND

Sebaceous gland tumors are a rare type of neoplasm. In some cases they have been associated with visceral tumors in patients with Muir-Torre syndrome, a hereditary form of nonpolyposis colorectal cancer. The aim of this study was to review the diagnosis and follow-up of a series of patients with sebaceous gland tumors to assess how many met the criteria for Muir-Torre syndrome.

PATIENTS AND METHODS

A search was performed of records from 1990 to 2005 in the database of the Department of Dermatology of the Consorcio Hospital General Universitario de Valencia in Valencia, Spain, to identify patients with sebaceous gland tumors. The biopsy material was reviewed to confirm the diagnosis. We also searched the patient histories for information suggestive of a diagnosis of Muir-Torre syndrome; when the histories were incomplete, we contacted the patients by telephone.

RESULTS

We identified 20 patients diagnosed with sebaceous gland tumors, but after reviewing the biopsy material diagnosis was only confirmed in 12. Two patients belonged to a family with a history of visceral tumors that met the clinical criteria for hereditary nonpolyposis colorectal cancer syndrome. Follow-up was not uniform in all patients and not all underwent the same tests.

CONCLUSIONS

It is essential to rule out the presence of Muir-Torre syndrome in patients with sebaceous gland tumors. The use of new techniques such as immunohistochemistry or detection of microsatellite instability may help to identify families at increased risk of Muir-Torre syndrome.