Muir-Torre Syndrome Research Articles

Aggressive Sebaceous Gland Hyperplasia in a Young Girl With MSH2 Gene Mutation: A Rare Presentation.

Sebaceous gland hyperplasia is a benign cutaneous entity commonly seen in older men. Occasionally, it can develop in young patients on immunosuppression with cyclosporine or in adolescent boys in the peripubertal age group. It is extremely rare in young children with no reports of eyelid involvement. It is believed to have no systemic associations, unlike sebaceous adenoma, which is associated with Muir-Torre syndrome. Herein, we present a rare case of a young girl with recurrent and aggressive eyelid sebaceous hyperplasia who was treated by a wide local excision of the lesion. The histopathology showed intact nuclear expression of mismatch repair proteins MLH 1, MSH 2, MSH 6, and PMS 2, and the genetic testing revealed a missense mutation in the MSH2 gene.

Overall drivers of mortality in sebaceous carcinoma patients with and without Muir-Torre syndrome: a population-based analysis

Overall drivers of mortality in sebaceous carcinoma patients with and without Muir-Torre syndrome: a population-based analysis

MSH2-Mutated Lynch Syndrome With 9 Synchronous Colon and Rectum Adenocarcinomas: An Extremely Rare Case Report

Synchronous colorectal carcinoma is having more than 1 primary carcinoma detected in a single patient at the same time or within 6 months of tumor diagnosis. Metachronous colorectal carcinoma is the presence of more than 1 primary carcinoma detected consecutively in a single person after a set time interval. Patients with Lynch syndrome and Muir-Torre syndrome (a subset of Lynch syndrome) inherit a germline mutation in 1 of the mismatch repair (MMR) genes. Patients with synchronous colorectal carcinoma have a higher proportion of MMR-mutated cancers than patients with solitary colorectal carcinoma. Most studies in the literature indicate that patients with synchronous colorectal cancers typically have only 2 carcinomas. However, there have been reports of a single patient having up to 6 synchronous carcinomas in the large intestine. This report discusses a patient with 9 simultaneous colorectal cancers at the initial diagnosis, along with a history of bladder cancer, sebaceous adenoma, and duodenal adenoma, associated with a germline mutS homolog 2 ( MSH2) mutation. Additionally, the report explores various aspects of having synchronous colorectal cancers. More studies are needed to clarify the clinicopathologic and molecular landscape of these rare tumors and identify the best management and treatment strategies for these patients.

Skin as a Reflection of Gut Health: An Overview of Dermatological Manifestations in Primary Neoplastic and Autoimmune Gastrointestinal Disorders.

Gastrointestinal (GI) diseases can present with several extraintestinal manifestations, and cutaneous signs and symptoms are most frequent. Although conventionally GI and skin are considered two entirely separate organ systems, they are closely correlated in origin. An increasing amount of data highlights the complex relationship between GI and dermatological conditions. This review article aims to particularly explore the clinical correlation between neoplastic and autoimmune GI disorders and skin manifestations, which serve as clinical indicators of these diseases. Neoplastic diseases including pancreatic cancer, gastric adenocarcinoma, Muir-Torre syndrome, carcinoid syndrome, and malignant and benign colorectal polyposis syndromes can be accompanied by skin conditions like pancreatic panniculitis, acanthosis nigricans, keratoacanthomas, necrolytic migratory erythema, melanotic macules, oral papillomas and osteomas, respectively. Autoimmune diseases including celiac disease, autoimmune liver conditions and inflammatory bowel disease (IBD) have been linked to dermatological manifestations such as xanthomas, morphea, psoriasis, dermatitis herpetiformis, erythema nodosum and epidermolysis bullosa acquisita. The skin manifestations can precede the GI symptoms and indicate the severity of the underlying condition, serving as a significant diagnostic marker earlier in the disease. Resolution of skin findings can also indicate the efficacy of treatment strategies and provide prognostic utility. Further research is essential to outline the underlying mechanisms linking dermatological and GI diseases and there is an immediate need for collaborative efforts between dermatologists and gastroenterologists.

FREQUENCY OF LOSS OF MISMATCH REPAIR PROTEINS’ IMMUNOHISTOCHEMICAL EXPRESSION IN SEBACEOUS NEOPLASMS, POTENTIAL MARKERS/TOOLS INDICATING THE POSSIBILITY OF MUIR-TORRE SYNDROME

Screening for Muir-Torre Syndrome (MTS) using Mismatch Repair (MMR) gene immunohistochemistry (IHC) on sebaceous neoplasms (SNs) is technically feasible. Research for this indication is limited, especially in Asia. To address this knowledge gap, we examined the frequency of loss of IHC staining of MMR proteins in SNs. Methods: We conducted a cross-sectional study including 98 patients (120 SNs). Eleven out of 98 patients had concurrent or subsequent SNs. Results: The size and type of tumor showed a significant association with MMR loss. Fifteen (12.5%) sebaceous adenomas, 12 (10.0%) sebaceous, and 93 (77.5%) sebaceous carcinomas were included in the study—sixty-one (50.83 %) SNs presented with loss of one or more MMR proteins. Isolated loss of MSH2 was the most common IHC pattern (27.8%). Fifty cases (29.58%) showed a combined loss of MSH2 and MSH6, and 40 (23.66%) showed a combined loss of MLH1 and PMS2. Most SAs showed isolated loss of MLH1 and PMS2 (7, 26.9% each). Sebaceomas showed isolated loss of MSH2 and MSH6 as the most common (4, 33.3%) pattern. Isolated loss of MSH2 only (37, 28.2%) was the predominant pattern of IHC loss in SCs. Weak to fragile associations between MMR protein status and histopathological findings were observed, with the most notable association being between MLH1 and ulceration on the surface. The models have an accuracy of around 50%, indicating moderate prediction capability. In our cohort, personal and family history was available in 33 cases (25 out of 98 patients). Conclusion: We recommend that MMR IHC be performed routinely on all SNs, considering clinicopathological factors of the lesions, mainly the anatomic site and tumor type. The panel should include antibodies against all four MMR proteins.

Analysis of gene mutation in a family with Muir-Torre syndrome accompanied with extraorbital cystic sebaceous carcinoma

This study reported a family of MLH1 mutation-induced Muir-Torre syndrome (MTS) and evaluated it's clinical and genetic characteristics. A 51 year-old patient with extraorbital cystic sebaceous and colon adenocarcinoma diagnosed in November 2021 in Zhongshan Hospital of Xiamen University was included. The clinical data of the family were collected and a pedigree chart was drawn, which was in line with the Chinese Lynch syndrome diagnostic criteria and was a typical MTS family. NM_000249.4:c.298C>T(p.R100*) of MLH1 gene in exon 3 was detected by whole exome sequencing and multiplex ligation dependent amplification, which is a pathogenic mutation. After the pathogenic mutation was identified, Sanger sequencing was performed on 4 direct members of the family for MLH1 gene, and 3 family members were found to have detected the mutation and included in MTS risk control. Until December 25 2023, follow-up showed the proband patients were not suffered from recurrence or new occurrence of skin or gastrointestinal tumors. The study reported a typical MTS family and found a possible pathogenic nonsense mutation in the MLH1 gene, which provides new evidence for the pathogenicity of this mutation.

Skin cancer-associated genodermatoses in skin of color patients: a review.

Skin cancers are associated with a large number of genodermatoses. Existing knowledge and guidelines on the presentations of these genodermatoses focus disproportionately on White patients. Our goal is to identify notable characteristics in location, frequency, and severity of cutaneous findings along with the median age of skin cancers in skin-of-color (SOC) patients with skin-cancer-associated genodermatoses to improve diagnosis rates. We searched for genodermatoses on six databases. Each case report or case series was reviewed, including reports, published in English, containing adult patient descriptions. Duplicate manuscripts were removed using EndNote. The following case-level data were collected from the manuscripts: age, gender, patient country or region of origin, author country/continent of residence, skin cancer-related, and other key dermatologic features. 381 published articles, with a total of 578 SOC patients, met criteria for inclusion. SOC patients can present with fewer classic findings, such as a lower incidence of basal cell carcinomas (44%) in SOC Gorlin syndrome patients than palmar pits (66%) and mandibular cysts (66%). Differences between SOC populations were also noted, such as leukoplakia being more common in Asian dyskeratosis congenita patients (80%) in comparison to African dyskeratosis congenita patients (44%). SOC patients also have varying onset of skin cancer depending on the genodermatosis, from a median of 25years of age in Rothmund-Thomson syndrome to 53 in Muir-Torre syndrome. In this review, SOC patients with genodermatoses can have varying presentations. Being cognizant of these characteristics may lead to earlier diagnosis and interventions to mitigate skin-cancer-related morbidity in SOC patients.

S1‐Leitlinie Talgdrüsenkarzinom

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 system therapies such as chemotherapy or immunotherapy can be considered. The procedure should be determined individually in an interdisciplinary tumor board. Close follow-up care is recommended for these potentially aggressive carcinomas.

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.

Sebaceous carcinoma in a 54-year-old Black African man after cancer chemotherapy: a case report

BackgroundSebaceous carcinoma is a very rare malignant skin adnexal tumor that is occasionally aggressive. We have not seen a case of sebaceous carcinoma in our center in the last 10 years. It is extremely rare in Black Africans.Case presentationWe described the case of a 55-year-old man African man who presented to our ophthalmologist with complaints of growth on the right upper eyelid for 8 months. He had surgery and chemotherapy for rectal carcinoma 6 years prior to presentation and received his last dose of chemotherapy 5 years before seeing our ophthalmologist. There was a history of spontaneous unprovoked bleeding from the lesion. He subsequently underwent surgical excision under general anesthesia. Histology of the mass showed an effaced architecture due to proliferating malignant epithelial cells disposed as trabecules, solid nests, and tongues. The microscopic features of widespread multivacuolated cytoplasm of the neoplastic cells led us to conclude that the tumor was a sebaceous carcinoma. The patient is alive and well.ConclusionSebaceous carcinoma is a rare malignant skin adnexal tumor in Black Africans. It can present as an eyelid mass with spontaneous bleeding. It can follow cancer chemotherapy either because of its association with other tumors in Muir–Torre syndrome or because of mutagenic effects of chemotherapeutic agents.

Expanding the Spectrum of Skin Neoplasms in Muir-Torre Syndrome: Beyond Sebaceous Tumours.

Expanding the Spectrum of Skin Neoplasms in Muir-Torre Syndrome: Beyond Sebaceous Tumours.

Muir-Torre syndrome presenting as sebaceous adenoma and papillary thyroid carcinoma

Muir-Torre syndrome presenting as sebaceous adenoma and papillary thyroid carcinoma

Androgen Receptor Immunohistochemistry is Superior to PRAME for the Differentiation of Sebaceous Carcinoma From Primary Cutaneous Basaloid Mimics.

Cutaneous sebaceous neoplasia comprises a spectrum of disease ranging from benign adenomas to malignant carcinomas. The hallmark of these lesions is sebaceous differentiation. However, poorly-differentiated sebaceous carcinoma (SC), which lacks significant overt sebaceous differentiation, can show morphologic overlap with a variety of other basaloid cutaneous neoplasms. The accurate classification of SC is essential not only for diagnosis, but also because of the potential association with Muir-Torre syndrome. Androgen receptor (AR) is a sensitive, but not entirely specific immunohistochemical marker that has been used for the diagnosis of SC. PReferentially expressed Antigen in MElanoma (PRAME) demonstrates strong cytoplasmic labeling of mature sebocytes and has been reported to be expressed in a variety of sebaceous neoplasms, including in the basaloid cell component. Therefore, we sought to compare the diagnostic use of cytoplasmic PRAME expression with that of AR for the distinction of SC from a cohort of basaloid cutaneous mimics; namely basal cell carcinoma, basaloid squamous cell carcinoma, pilomatricoma, cutaneous lymphadenoma, and extra-mammary Paget disease. We report that cytoplasmic PRAME expression is uncommon in poorly differentiated SC, and although specific, it shows very low sensitivity (22%). In contrast, AR was moderately sensitive (66%) and highly specific (92%) for the distinction of SC from basaloid mimics. These attributes, in addition to the nuclear expression of AR in the sebocytic and basaloid components of SC, suggest that AR is superior to PRAME for the diagnosis of SC.

Clinical Outcomes in Sebaceous Carcinoma: A Retrospective Two-Center Cohort Study.

Sebaceous carcinoma (SC) is a rare, potentially recurrent, and life-threatening cutaneous malignancy that can be associated with Muir-Torre syndrome (MTS), a DNA mismatch repair-driven genodermatosis. Earlier studies examining factors associated with recurrence have focused on periocular tumors only. Examine outcomes of SC and identify factors associated with recurrence. Retrospective study from 2 tertiary care centers. Sixty-seven cases from 63 patients were identified, including 7 cases of MTS and 13 arising in the context of immunosuppression. Fifty-five cases (82.1%) were treated with complete circumferential peripheral and deep margin assessment (CCPDMA) methods. Five recurrences developed during the postoperative period. On univariate analysis, periocular location (odds ratio [OR] 7.6, p = .0410), and lesion size ≥2 cm (OR 9.6, p = .005) were associated with recurrence, whereas CCPDMA (OR 0.052, p = .0006) was inversely associated with recurrence. On multivariate analysis, only lesion size ≥2 cm (OR 9.6, p = .0233) and CCPDMA approaches (OR 0.052, p = .007) were significant. Non-complete circumferential peripheral and deep margin assessment methods and large lesion size were independent risk factors predicting recurrence, whereas anatomic subtype and MTS status were not. These findings can assist in identifying SC cases that may benefit from more aggressive treatment and closer surveillance.

The prevalence of lynch syndrome (DNA mismatch repair protein deficiency) in patients with primary localized prostate cancer using immunohistochemistry screening

BackgroundProstate cancer is one of the most heritable human cancers. Lynch syndrome is an autosomal dominant inheritance caused by germline mutations in DNA mismatch repair (MMR) genes, which are also associated with an increased incidence of prostate cancer. However, prostate cancer has not been defined as a Lynch syndrome-associated cancer. The proportion of Lynch syndrome patients in primary prostate cancers is unclear. In this study, we investigated MMR protein loss using universal immunohistochemical screening to determine the prevalence of Lynch syndrome in patients with localized prostate cancer who underwent radical prostatectomy.MethodsOne hundred twenty-nine surgical specimens from radical prostatectomy performed at Toranomon Hospital between 2012 and 2015 were retrospectively tested using universal screening with immunohistochemistry staining for expression of the MMR proteins MLH1, PMS2, MSH2, and MSH6. For all suspected MMR-deficient patients, germline genetic tests focusing on MMR genes were performed.ResultsMMR protein loss was found in only one patient (0.8%) who showed dual MSH2/MSH6 loss. This patient showed a single nucleotide pathogenic germline mutation from c.1129 C to T (p.Gln377*) at exon 7 in the MSH2 gene. He was diagnosed with a primary prostate cancer at 66 years of age. He had a documented history of Lynch syndrome (Muir–Torre syndrome) with previous colon cancer, sebaceous tumor, and keratoacanthoma as well as subsequent bladder cancer, all of which also showed dual MSH2/MSH6 loss. He also had a strong family history of colorectal and other Lynch syndrome-associated cancers. The pathological stage was pT3aN0M0, and the pathological grade was Gleason 7(4 + 3) with tertiary pattern 5.ConclusionsIn this study, immunohistochemical screening of MMR proteins for Lynch syndrome was performed in a series of prostate cancer cases. The prevalence of Lynch syndrome in localized prostate cancer was 0.8%, which is low compared with other Lynch syndrome-associated 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.

Recent updates on the management of ocular sebaceous gland carcinoma

Ocular sebaceous gland carcinoma (SGC) is a relatively rare, slow growing, but most aggressive and life-threatening tumor. It accounts for around 1% of all cutaneous malignancies. In Caucasians, SGCs are rare accounting for 1-5.5% of eyelid malignancies with a high incidence rate (28-60%) reported in the Asian population. In most SGCs no obvious etiology has been identified but few cases are associated with Muir-Torre syndrome. The dysregulation of several cell signaling pathways has been reported in tumorigenesis of SGC. Recently genome sequencing of periocular SGC revealed several gene mutations like TP53 and RB1 genes. Ocular SGC is known as the ‘great masquerader’ as it mimics several benign and inflammatory conditions like chalazion and chronic blepharitis/ blepharoconjunctivitis which may be responsible for delayed diagnosis and high mortality. Clinico-pathologically ocular SGC can be broadly categorized into nodular and pagetoid subtypes. The latter is more aggressive and associated with a high rate of lymph node metastasis and recurrence hence requiring aggressive multimodal treatment. More aggressive features associated with poor prognosis include involvement of both eyelids, infiltrative growth pattern, multicentric in origin with a pattern of spread to surrounding structures like pagetoid spread, vascular, lymphatic and orbital invasion. Although wide surgical excision with tumor-free margin is the gold standard treatment for the localized nodular type of ocular SGC, but the management of advanced-stage disease, invasive or aggressive lesions and recurrence is challenging and often needs a multidisciplinary approach that can reduce the mortality rate in patients with SGC. In this review article, we report recent research in molecular pathogenesis, clinicopathological features, the importance of TNM staging, sentinel lymph node biopsy, map biopsy and immunohistochemical evaluation of tumor markers like p,Ki-67, bcl-1, and p. We also emphasized the treatment of ocular SGC, i.e. surgical excision & reconstruction, topical therapy, neoadjuvant chemotherapy, targeted therapy, and radiation therapy.

BG13 A rare case of Muir–Torre syndrome

Abstract Muir–Torre syndrome is a rare variant of hereditary nonpolyposis colorectal cancer, also known as Lynch syndrome. It is caused by a defect in mismatch repair genes, which are most commonly inherited in an autosomal dominant fashion. It is characterized clinically by sebaceous neoplasms of the skin associated with at least one visceral malignancy, with colon cancer being the most frequent. The most common genetic defects responsible are in MLH1, MSH2 and MSH6, which results in an increased frequency of unrepaired base mismatching during DNA replication and subsequent microsatellite instability, predisposing to cancer. We present a case of a 59-year-old man with a history of colon cancer who was referred with a rapidly growing irregular nodule on his lower back for the past 2 months, concerning for an amelanocytic melanoma. An excision biopsy was arranged, and subsequent histology demonstrated a sebaceoma. Immunohistochemistry for mismatch repair genes showed loss of expression for MSH2 and MSH6. Upon further questioning, it was found that he had a strong family history of colon cancer (father, brother and two sisters), and he developed colon cancer at 36 years of age, which was treated with a pancolectomy. Genetic testing revealed a mutation in MSH2. Given this history, annual follow-up was arranged for skin surveillance.

BI09 Microsatellite instability and loss of mismatch repair proteins in nonmelanoma skin cancer and treatment-resistant phenotypically distinct precancerous lesions in Muir–Torre/Lynch syndrome: a multicentre retrospective study

Abstract DNA mismatch repair (MMR) gene mutations resulting in microsatellite instability (MSI) are associated in the pathogenesis of Muir–Torre syndrome (MTS), a variant of Lynch syndrome (LS). It is characteristically defined by the association of at least one sebaceous skin neoplasm and/or keratoacanthoma and a visceral malignancy. The presence of cutaneous lesions plays a vital role in the early detection and preventive cancer screening of the disease; however, nonmelanoma skin cancers (NMSCs) and their precursors are seldom reported. We conducted a retrospective multicentre study between 2011 and 2022 of adults with a confirmed genetic diagnosis of MTS/LS across two specialist institutions presenting with phenotypically distinct treatment-resistant precancerous skin lesions and/or NMSC with the associated loss of MMR expressions consistent with their germline mutations which are currently not recognized diagnostic features. Median age at the onset of precancerous/NMSC in eight individuals was 57.5 years, with an equal sex distribution. Lesions occurred mostly on the face (n = 14), followed by the forearms (n = 8), dorsum of the hands (n = 9), the legs (n = 4) and the chest (n = 1). Our study histologically and immunohistochemically examined MMR expressions and MSI in 20 precancerous and/or NMSCs. Loss of expression and MSI were found in actinic keratoses (AK) (n = 6/7), disseminated superficial actinic porokeratosis (DSAP; n = 1/2), squamous cell carcinoma (n = 4/5) and basal cell carcinoma (n = 4/4). Additionally, we found sebaceomas with atypia (n = 2/2). In 17 lesions, the loss of MMR expression and MSI were consistent with their germline mutations. We also discovered that all lesions identified with MSI had normal adjacent skin with no loss of MMR expression. Our observations suggest the detection of MSI, and MMR gene abnormality, play a critical role in the development of precancerous and NMSC other than sebaceous neoplasms in this disease. To date, the diagnostic criteria for MTS/LS do not include NMSC and their precursors, and these have rarely been reported. We note a clinically distinct presentation of widespread erythematous scaly lesions resembling AK/DSAP, resistant to multiple treatments, which is an additional recognizable clinical feature in this patient subgroup. This is an important association in cancer-prone individuals and immunohistochemistry testing for MMR genes should be encouraged. This can be a powerful investigative tool as AK/DSAP are easily identifiable, numerous and readily accessible for DNA analysis; therefore, detecting the presence of MSI in the skin may aid in screening individuals promptly. MTS/LS is best managed by a multidisciplinary team with close surveillance for visceral malignancies, highlighting the importance of routine monitoring for precancerous and nonsebaceous skin cancers.

Sebaceous Neoplasms.

Sebaceous neoplasms describe a group of tumors with sebaceous differentiation commonly seen in lesions located primarily in the face and neck. The majority of these lesions are benign, while malignant neoplasms with sebaceous differentiation are uncommon. Sebaceous tumors present a strong association with the Muir-Torre Syndrome. Patients suspected with this syndrome should undergo neoplasm excision, followed by histopathologic and additional immunohistochemistry and genetics examinations. Clinical and dermoscopic features of the sebaceous neoplasms, as well as management procedures collected from the literature analysis regarding sebaceous carcinoma, sebaceoma/sebaceous adenoma, and sebaceous hyperplasia are described in the current review. A special note is made for describing the Muir-Torre Syndrome in patients presenting multiple sebaceous tumors.