Adenomatoid tumors of ovary mimicking malignancy: report of 2 cases and literature review

Abstract

Background Adenomatoid tumors (ATs) are benign tumors originating from the mesothelium. ATs of the ovary are rare, and can easily be confused with malignancy due to the histomorphological diversity. Thus, it is difficult in histopathological and differential diagnosis, especially during intraoperative frozen pathological diagnosis, which directly affects the resection scope of surgery. Case presentation In this study, we reported two patients (58 and 41 year old) with ovarian ATs. AT of patient 1 occurred in both ovaries at different time points and she had been diagnosed with Hashimoto's thyroiditis. AT of patient 2 occurred in right ovary. Intraoperative frozen pathological diagnosis was performed in both cases and laparoscopic salpingo-oophorectomy was undergone on the lesion side according to benign freezing diagnostic result. Ovarian ATs, the final diagnoses of the 2 cases were concluded after histological, extensive immunohistochemical (IHC), histochemical, and fluorescence in situ hybridization analyses. Conclusions Our results show that ovarian ATs may not be related to BAP1 or CDKN2A/p16 mutations. In addition, the case 1 suggests that ATs may be associated with immune dysregulation. When encountering such similar lessions, we recommend that a series of immunohistochemical, histochemical and molecular biological techniques should be used for diagnosis and differential diagnosis to avoid misdiagnosis. Improving understanding of the rare ovarian ATs which mimic malignancy is necessary to prevent overresection.