Recent updates in gynaecological pathology

Abstract

Updates on pathology of the female genital tract particularly that highlighted in the 2014 WHO classification, will discussed. Related to ovarian serous borderline tumour, “invasive implants” should be diagnosed as low-grade serous carcinoma while non-invasive tumour with micropapillary pattern and moderate cytologic atypia exceeding an area of 5 mm should be classified as non-invasive low grade serous carcinoma. A new category of seromucinous tumours has been created, characterized by mixture of serous and mucinous and other cell types. Urothelial / transitional cell carcinoma is now recognized as high grade serous carcinoma. Squamous cell carcinoma is moved to the monodermal teratoma category. A simplified two-tier classification on endometrial hyperplasia, “hyperplasia without atypia” and “atypical hyperplasia”, is introduced. Endometrioid intraepithelial neoplasia (EIN) is considered as an alternative term for atypical hyperplasia. High grade endometrial stromal sarcoma is reintroduced under uterine sarcoma while the term “undifferentiated uterine sarcoma” is adopted to replace “undifferentiated endometrial sarcoma” since it may arise from endometrium or myometrium. At the lower female genital tract, a two-tier system of low- and high-grade squamous intraepithelial lesions (SIL) is introduced for the cervix, vulva and vagina. This is considered to be histologically more reproducible than the three-tier cervical (vulva, vagina) intraepithelial neoplasia (-IN) 1 to 3.Mucinous carcinoma, gastric type, is a recently introduced entity incorporating cases of minimal deviation adenocarcinoma (adenoma malignum). Differentiated vulval intraepithelial neoplasia (VIN) is defined as HPV-negative squamous intraepithelial proliferation with abnormal keratinocyte differentiation and basal cell atypia. It is believed to be associated with keratinizing squamous cell carcinoma, lichen sclerosus and lichen planus. No reliable biomarker is currently available. The entity superficial myofibroblastoma is also introduced. Under gestational trophoblastic disease, “abnormal (non-molar) villous lesions” refer to various lesions with histological features resembling partial mole. More emphasis on genetic profiles of hydatidiform mole is made.