Uncommon Mixed Endometrial-Myometrial Benign Tumors of the Reproductive Tract: Literature Review

<b><i>Background:</i></b> We reviewed published cases of uterus-like mass (U-LM), endomyometriosis, polypoid adenomyoma (PA), adenomyomatous polyp, atypical PA (APA), and adenomyoma. <b><i>Search Methods:</i></b> PubMed, Medline, and Scopus searches of all cases published in the databases till November 26, 2018. <b><i>Results:</i></b> We identified 45 case reports of U-LM in the pelvis, 10 cases of endomyometriosis, 44 cases of adenomyomatous polyp, 466 cases of APA and case series of adenomyoma and PA. Most case reports focused on histological description of removed lesions with no or very limited clinical correlates. Histological descriptions were often used interchangeably, which creates considerable confusion. It is unclear if endomyometriosis warrants inclusions as a distinct entity, since the distinction is blurred between adenomyomatous polyp and PA. The glandular epithelium in atypical polypoid adenomyoma exhibits atypia and the lesions have a tendency to recur with a risk of malignant transformation. Smooth muscle metaplasia and Müllerian fusion defects have been proposed as etiology, but it is possible that the lesions do not share a common origin. <b><i>Conclusion:</i></b> There is need for more detailed and structured description of reported cases including clinical presentation and associated pathology.