Mesonephric adenocarcinoma of the uterine cervix with a prominent spindle cell component

Abstract Mesonephric adenocarcinomas (MAs) with spindle cell components are rare malignant tumors of the cervix. We conducted a retrospective analysis of MAs with spindle cell components. Clinicopathological data were collected from electronic surgical pathology records, and immunohistochemistry and targeted next-generation sequencing (NGS) were performed. The study included three postmenopausal women aged 51 to 60 years. All patients underwent hysterectomy with bilateral salpingo-oophorectomy and pelvic lymph node dissection. There were no recurrences or deaths after surgery. The NGS analysis identified KRAS mutations in two cases and a lone PIK3CA mutation in one case. Spindle cell components could be a morphological feature of MAs in the advanced stage. Spindle cell components in MAs are diagnostic pitfalls, and the use of immunohistochemical panels and molecular detection is recommended for cases with overlapping morphological features. While KRAS mutation is the most frequent molecular alteration, PIK3CA mutation can be identified independently in cases without KRAS mutation.