Dedifferentiated Mesonephric-like Adenocarcinoma of the Uterine Corpus

Background/Aim: We present a case of uterine dedifferentiated mesonephric-like adenocarcinoma (MLA). Case Report: A 54-year-old woman underwent total hysterectomy for a uterine mass under the impression of a uterine sarcoma. Histologically, MLA exhibited various growth patterns including tubular and glandular architecture. Undifferentiated carcinoma (UC) displayed discohesive tumor cells without any obvious architecture. Immunohistochemically, UC was positive for epithelial markers in very few scattered tumor cells. MLA exhibited the wild-type p53 expression pattern, whereas UC showed a uniform and strong p53 immunoreactivity. Targeted sequencing analysis revealed an identical Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation in both components. A pathogenic missense tumor protein 53 (TP53) mutation was detected in UC, but not in MLA. Conclusion: The mutant p53 expression pattern exclusively detected in UC was concordant with the presence of missense TP53 mutation. Our observations suggested that TP53 mutation is associated with the possible transformation from MLA to UC.