1/3. A case of multiple sebaceous epithelioma: analysis of microsatellite instability.Sebaceous gland tumor is a rare disease that is a sign of muir-torre syndrome, an autosomal, dominantly inherited genodermatosis characterized by the presence of at least one sebaceous gland tumor and a minimum of one internal malignancy. Recent studies have indicated that defective dna mismatch repair occurs in muir-torre syndrome. Cutaneous lesions may occur before diagnosis of the internal cancer. We describe a 64-year-old male patient with multiple sebaceous epitheliomas with no evident internal malignancy. microsatellite instability, determined by examining dinucleotide CA repeats at the microsatellite loci, was observed in DNA from one sebaceous epithelioma but not from the other two sebaceous epitheliomas or from one basal cell epithelioma with sebaceous differentiation, suggesting that this condition is unlikely to be due to germ-line mutation of mismatch repair genes.- - - - - - - - - - ranking = 1keywords = microsatellite instability, microsatellite, instability (Clic here for more details about this article) |
2/3. muir-torre syndrome: role of the dermatopathologist in diagnosis.muir-torre syndrome (MTS) is an autosomal dominantly inherited disorder characterized by sebaceous lesions and visceral malignancies. The defect is thought to be the result of a mutation in mismatch repair genes and associated with microsatellite instability. Two cases whose diagnoses were suggested first by the dermatopathologist are discussed. The first is a 47-year-old white man who over the past 6 years developed multiple sebaceous lesions. Due to the number of sebaceous lesions and their morphology, the possible diagnosis of MTS was suggested by the dermatopathologist. Subsequently, a lesion in the right colon was found during colonoscopy that proved to be a poorly differentiated cecal adenocarcinoma. A pedigree analysis revealed other family members afflicted with multiple malignancies. genetic testing of the colonic adenocarcinoma showed microsatellite instability. The second patient is a 50-year-old white man who underwent biopsy of a skin lesion that showed features of both a sebaceous hyperplasia and sebaceous adenoma. Because of the mixed, unusual features of the lesion, the dermatopathologist suggested the diagnosis of MTS. It was later confirmed that the patient had a history of malignancies of the colon and kidney as well as a family history significant for multiple malignant neoplasms. These cases demonstrate the important role of the dermatopathologist in alerting the clinician to the possibility of muir-torre syndrome when the diagnosis of a sebaceous neoplasm is made, especially when unusual histologic features are observed.- - - - - - - - - - ranking = 0.49585196049751keywords = microsatellite instability, microsatellite, instability (Clic here for more details about this article) |
3/3. An illustrative case of muir-torre syndrome: contribution of immunohistochemical analysis in identifying indicator sebaceous lesions.BACKGROUND: muir-torre syndrome (MTS) is an autosomal dominant genodermatosis characterized by the association of at least 1 cutaneous sebaceous tumor and 1 internal malignancy, often arising in the gastrointestinal tract. It is secondary to germline mutations in dna mismatch repair genes, mainly MLH-1 and MSH-2. OBSERVATIONS: We report the case of a 54-year-old man with a 2-year history of skin-colored papules clinically reminiscent of large sebaceous hyperplasias on the nose and back, but histologically diagnosed as sebaceous adenomas and epitheliomas. His family history was positive for colon cancer in the mother and 2 brothers. A colonoscopy done during the hospitalization revealed 2 sessile polyps in the left colon, both showing a low-grade dysplasia on the biopsy specimen. Immunohistochemical staining performed on the cutaneous and colic biopsy specimens revealed a lack of expression of MSH-2 and MSH-6. genetic testing revealed microsatellite instability in the colon and cutaneous tumors. CONCLUSION: The immunohistochemical testing for MSH-2, MSH-6, and MLH-1 is useful for rapid identification of an underlying mismatch repair defect and early diagnosis of MTS.- - - - - - - - - - ranking = 0.24792598024876keywords = microsatellite instability, microsatellite, instability (Clic here for more details about this article) |