Muir-Torre syndrome: the curious case of wobbly microsatellites and their mucosal Lynch


  • Robert A. Elmore Department of Pathology, CHI Health Creighton University Medical Center, Omaha, Nebraska, USA
  • Mary K. Dick Creighton School of Medicine, Omaha, Nebraska, USA
  • Poonam K. Sharma Department of Pathology, CHI Health Creighton University Medical Center, Omaha, Nebraska, USA



Lynch syndrome, Muir-Torre syndrome, Microsatellite, MSH2


MSH2 mismatch repair gene is commonly associated with Lynch syndrome; however, Lynch syndrome’s phenotypic variant, Muir-Torre syndrome is a lesser known entity comprising a spectrum of benign to malignant sebaceous neoplasms and is often the first etiology of a more significant prodromal syndrome. Both syndromes encompass gastrointestinal, genitourinary tract, and prostatic pathologies. We present a 15-year patient progression starting with new sebaceous hyperplasia and congenital melanocytic nevus skin lesions presenting in a 38-year-old caucasian male. After approximately four years additional cutaneous lesions began continuously appearing identified as: ulcerated sebaceoma, basal cell carcinoma, sebaceous hyperplasia, sebaceous adenoma, and hidradenoma. The patient went on to develop prostate adenocarcinoma and tubular adenoma of the ascending colon and rectum. Immunohistochemical staining demonstrated MSH2 and MSH6 instability and patient was recommended for Lynch Syndrome genetic testing. Later genetic analysis showed pathologic variant of MSH2 confirming Muir-Torre Syndrome. When multiple pathologies are involved that affect ectoderm differentiation, a diagnostic workup for microsatellite instability is recommended in association with a genetic counselor consultation. When a familial defect in a DNA repair enzyme (MSH1, MSH2, etc.) is known, we recommend PCR amplification for microsatellite instability in offspring between ages 5-15 to reduce morbidity and mortality in this population.


Robertson DM, Biaggioni I. Primer on the Autonomic Nervous System. Amsterdam: Elsevier Academic Press; 2012.

Brinster NK, Liu V, Diwan H, McKee P. High-Yield Pathology Dermatopathology. Philadelphia: Elsevier/Saunders; 2011.

Johnston R. Weedon's Skin Pathology Essentials. Elsevier; 2012.

Shalin SC, Lyle S, Calonje E, Lazar AJF. Sebaceous neoplasia and the Muir-Torre syndrome: important connections with clinical implications. Histopathology. 2010;56(1):133-47.

Elston DM, Ferringer T, Ko CJ. Dermatopathology. Philadelphia: Saunders/Elsevier; 2014.

Švec J, Schwarzová L, Janošíková B, Štekrová J, Mandys V, Kment D, et al. Synchronous gastric and sebaceous cancers, a rare manifestation of MLH1-related Muir-Torre syndrome. Int J Clin Exp Pathol. 2014;7(8):5196-202.

Gianotti R, Alessi E. Clear Cell Hidradenoma Associated with the Folliculo-Sebaceous-Apocrine Unit. Am J Dermatopathol. 1997;19(4):351-7.

Ackerman AB. Algorithms for Histologic Diagnosis of Inflammatory Skin Diseases. New York: Ardor Scribendi; 2005.