Mesonephric-like adenocarcinoma as an unexpected histological result after fertility saving procedure for presumed adenomyosis: a case report.

INTRODUCTION

We report an unexpected case of mesonephric-like adenocarcinoma initially treated as a diffuse adenomyosis in a patient presenting with primary infertility. The aim of this report is to raise clinical awareness about the risk of a diagnostic pitfall where an unexpected malignancy can mimic diffuse adenomyosis. The patient's main concerns and important clinical findings: A 41-year-old patient referred to a tertiary minimally invasive gynecological center in June 2023 for primary infertility, heavy menstrual bleeding, and a 5 x 6 cm myometrial mass diagnosed as diffuse adenomyosis on ultrasound scan.

THE PRIMARY DIAGNOSES INTERVENTIONS AND OUTCOMES: An open cytoreductive resection of adenomyosis with uterine cavity reconstruction was planned due to worsening abnormal uterine bleeding and two failed in vitro fertilization attempts. An unexpected Mesonephric-like adenocarcinoma with only small foci of healthy tissue was identified on histopathological examination, and immunohistochemical staining. Consequently, the patient had a total abdominal hysterectomy with bilateral salpingo-oophorectomy and systematic pelvic lymphadenectomy. This was followed by six cycles of paclitaxel and carboplatin plus pembrolizumab-based immunotherapy.

CONCLUSIONS

This case highlights the importance of thorough evaluation of all atypical myometrial lesions, including adenomyosis, where pre-conception surgical excision and histopathological evaluation are often deferred in most patients.