Invasive carcinoma of breast with sebaceous pattern

LIU Ye; CHEN Ji; JIANG Dong-dong; LI Li; BAO Shu-you; GE Hong-jun; LI Kui-fang

doi:10.3969/j.jssn.1007-8096.2024.07.009

Abstract：Objective To investigate the clinicopathological features,immunophenotype,differential diagnosis,molecular features and prognosis of sebaceous breast carcinoma.Methods one case of sebaceous breast carcinoma diagnosed in the Department of Pathology,Jiangyin Hospital of Traditional Chinese Medicine in 2023 was collected.Immunohistochemical staining,fluorescence in-situ hybridization and next-generation sequencing were performed,and literatures were reviewed.Results The patient was a 42-year-old woman who presented with a tumor of right breast.Two types of cells were seen under the microscope:one type was undifferentiated cells with perinuclear distribution and little cytoplasm;the other type was sebaceous adenoidal cells with abundant vacuolated cytoplasm,high-grade nuclei,pronounced nucleoli,and abnormally active nuclear mitosis,up to 39/10HPF.In situ lesions and lobular carcinomatosis were seen.Immunohistochemistry showed that ER and PR were negative.AR and CD15 were positive and without HER2 overexpression.Expression of p53 was mutant and Ki-67 proliferation index was 70％-80％,mismatch repair protein(MLH1,MSH2,MSH6,PMS2)were not deletively expressed.No germline mutations were detected in BRCA1/2 by next-generation sequencing,but somatic mutation of BRCAI and TP53 was found.Conclusion Sebaceous breast carcinoma is rare and belongs to the category of non-specific types of breast carcinoma,and diagnosis requires a combination of histomorphological and immunophenotypic considerations,and molecular detection shows that TP53 accompanies with BRCAI mutations.