Dermatologists play an important role in disease management for patients with Muir-Torre syndrome (MTS). In this resident takeover, Dr. Daniel Mazori talks to Dr. Mohammed Dany about the pathogenesis of MTS and its associated malignancies. “We are the ones who usually make the diagnosis, and we should know that these patients are at risk for developing several visceral malignancies and thus require screening,” Dr. Dany explained. They also review diagnostic clues and tools for dermatologists when treating patients with solitary sebaceous tumors.

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We also bring you the latest in dermatology news and research:

1. COVID-19 spurs telemedicine, furloughs, retirement

2. Evidence on spironolactone safety, COVID-19 reassuring for acne patients

3. COVID-19 decimates outpatient visits

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Things you will learn in this episode:

• Muir-Torre syndrome is an autosomal-dominant genetic disorder that predisposes patients to both cutaneous neoplasms and visceral malignancies.
• Sebaceous tumors are the hallmark of MTS and are rarely seen outside of this condition: “All three types of sebaceous tumors can be present in these patients: the adenomas, the epitheliomas, and the carcinomas,” Dr. Dany explains. Nonsebaceous skin tumors also can present in MTS, including rapidly growing keratoacanthomas and basal cell carcinomas.
• Patients with MTS should be further screened for colorectal, endometrial, ovarian, breast, lung, genitourinary, hematobiliary, hematopoietic, and central nervous system cancers. “Every Muir-Torre syndrome patient [also] should definitely see a dermatologist at least once a year for skin cancer screening,” Dr. Dany advises.
• In MTS, germline mutations in DNA mismatch repair genes lead to microsatellite instability, which drives the formation of tumors; however, MTS is not always genetic and is not always inherited. More research is needed on whether specific mutations put MTS patients at higher or lower risk for developing certain kinds of tumors.
• All patients presenting with a solitary sebaceous tumor should be worked up for MTS. Tumor location can be a helpful diagnostic indicator. “A sebaceous tumor that is inferior to the neck is most likely associated with Muir-Torre syndrome; on the other hand, sebaceous tumors on the head and neck can be either a manifestation of Muir-Torre but can also be spontaneous,” Dr. Dany advises.
• The Mayo MTS score is a helpful tool for risk stratification in MTS patients. “The score ranges from 0 to 5, and then a risk of 2 or more has 100% sensitivity for Muir-Torre syndrome and has an 81% specificity for predicting a germline mutation in the [DNA mismatch repair] genes,” Dr. Dany explains. Molecular testing should be performed to confirm the diagnosis.
• Solitary sebaceous tumors in patients with low Mayo scores may be sporadic; therefore, further laboratory work-up is recommended to avoid misdiagnosis of MTS.
• Muir-Torre syndrome type 2, also known as autosomal-recessive colorectal adenomatous polyposis, is a new subtype of MTS that demonstrates an autosomal-recessive pattern of inheritance and microsatellite stability.
• Future research is needed to delineate pathways for targeted therapies that can shut down the formation of new sebaceous tumors, particularly sebaceous carcinomas. “If we are able to find a way to prevent the formation of those sebaceous tumors from showing up, then we will end up with less follow-up, [fewer] biopsies, and less concern from our end,” Dr. Dany explains.

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Hosts: Nick Andrews; Daniel R. Mazori, MD (State University of New York, Brooklyn)

Guests: Mohammed Dany, MD, PhD (University of Pennsylvania, Philadelphia)

Disclosures: Dr. Mazori reports no conflict of interest. Dr. Dany reports no conflict of interest.

Show notes by: Alicia Sonners, Melissa Sears

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