Variants of in situ carcinoma of the endometrium: Clear cell and gastrointestinal types, with a review of the literature

Gastric‐type glandular lesions of the female genital tract excluding the cervix: emerging pathological entities

“…Benign or atypical gastric-type mucinous lesions of the endometrium (without concurrent adenocarcinoma) have been variably described using the terms 'intestinal metaplasia', 'synchronous mucinous metaplasia and neoplasia', 'gastric (gastrointestinal)-type mucinous metaplasia', 'mucinous adenocarcinoma in situ' or 'adenocarcinoma in situ of gastrointestinal type'. 32,33,39,[53][54][55][56] We suggest the term 'gastric-type mucinous metaplasia/ mucinous metaplasia of gastric-type' to encompass cases with or without intestinal differentiation.…”

“…Endometrial gastric-type mucinous metaplasia may be an incidental finding, 32,39 but some patients present with abnormal uterine bleeding or watery/mucoid vaginal discharge. [53][54][55][56] These lesions affect women of both reproductive and postmenopausal age, and may be an isolated finding or associated with multifocal mucinous proliferations at other sites in the female genital tract and/or Peutz-Jeghers syndrome.…”

“…Some of these lesions occur within an endometrial polyp (usual or adenomyomatous-type). 32,54,56 In a minority of cases, a degree of cytological atypia is present, with nuclear enlargement, pseudostratification and hyperchromasia, sometimes accompanied by mitotic activity. 32,53,56 The terminology used for such foci has varied 53,56 and currently there is no consensus over the diagnostic criteria and terminology in these mucinous lesions.…”

“…32,54,56 In a minority of cases, a degree of cytological atypia is present, with nuclear enlargement, pseudostratification and hyperchromasia, sometimes accompanied by mitotic activity. 32,53,56 The terminology used for such foci has varied 53,56 and currently there is no consensus over the diagnostic criteria and terminology in these mucinous lesions. We suggest the term 'atypical mucinous proliferation of gastric-type' with a comment regarding the degree of nuclear atypia and that there is some evidence that this may be a precursor lesion to endometrial gastrictype adenocarcinoma.…”

“…A lobular architecture similar to LEGH is at least focally present in some cases, 32,39 which may impart an impression of mild glandular crowding due to tangential sectioning, but there should not be significant architectural complexity such as confluent growth or anastomosing papillary structures. Some of these lesions occur within an endometrial polyp (usual or adenomyomatous‐type) 32,54,56 . In a minority of cases, a degree of cytological atypia is present, with nuclear enlargement, pseudostratification and hyperchromasia, sometimes accompanied by mitotic activity 32,53,56 .…”