Molecular characteristics of endometrial cancer coexisting with peritoneal malignant mesothelioma in Li-Fraumeni-like syndrome

Background: Endometrial cancer that occurs concurrently with peritoneal malignant mesothelioma (PMM) is difficult to diagnose preoperatively. Case presentation: A postmenopausal woman had endometrial cancer extending to the cervix, vagina and pelvic lymph nodes, and PMM in bilateral ovaries, cul-de-sac, and multiple peritoneal sites. Adjuvant therapies included chemotherapy and radiotherapy. Targeted, massively parallel DNA sequencing and molecular inversion probe microarray analysis revealed a germline TP53 mutation compatible with Li-Fraumeni-like syndrome, somatic mutations of PIK3CA in the endometrial cancer, and a somatic mutation of GNA11 and JAK3 in the PMM. Large-scale genomic amplifications and some deletions were found in the endometrial cancer. The patient has been stable for 24 months after therapy. One of her four children was also found to carry the germline TP53 mutation. Conclusions: Molecular characterization of the coexistent tumors not only helps us make the definite diagnosis, but also provides information to select targeted therapies if needed in the future. Identification of germline TP53 mutation further urged us to monitor future development of malignancies in this patient and encourage cancer screening in her family.