[The 2019 FIGO classification for cervical carcinoma-what's new?]

Numerous therapeutic and prognostic studies of cervical carcinoma have necessitated a revision of the FIGO classification.For microinvasive carcinomas, the horizontal dimension is no longer considered and diagnosis and staging will solely be made by the depth of cervical stromal invasion. Lymphovascular invasion beyond the deepest point of stromal infiltration by tumor cells does not alter the stage.There will be a new subclassification of macroinvasive carcinoma confined to the uterine cervix, which will be made by largest tumor extension as follows: FIGO IB1/T1b1 - invasive carcinoma >0.5 cm depth of stromal invasion and ≤2 cm in largest dimension, FIGO IBII/T1b2: - invasive carcinoma >2 cm and ≤4 cm, FIGO IBII/T1b3 - invasive carcinoma >4 cm. Pelvic as well as para-aortic lymph nodes will be defined as regional nodes. Pelvic lymph node metastases only will be categorised as FIGO IIIC1/pN1a and para-aortic lymph node involvement with or without concomitant pelvic involvement will be FIGO IIIC2/pN1b. Uterine corpus as well as adnexal involvement are not relevant for staging purpose.

[Un- and dedifferentiated endometrial carcinoma : A rare entity with a wide range of differential diagnosis]

Dedifferentiated endometrial carcinomas (ECs) are composed of undifferentiated EC and a FIGO grade 1 or 2 endometrioid carcinoma. The undifferentiated component represents a malignant epithelial neoplasm with no obvious differentiation and immunohistochemical loss of PAX8, E‑cadherin and focal expression of EMA and/or CK18 and the predominant presence of nuclear staining for INI1 (SMARCB1) and BRG1 (SMARCA4). The main differential diagnoses include poorly differentiated endometrioid EC, neuroendocrine carcinoma, lymphoma, plasmocytoma, high-grade endometrial stromal sarcomas, undifferentiated uterine sarcomas (UUS), carcinosarcomas, and metastases to the endometrium. The histogenesis is not yet fully understood and molecular data are still limited. Some tumors represent a loss of MHL1 and PMS2 staining due to MLH1-promotor methylation. Rare cases are associated with Lynch syndrome or POLE mutation. The un- or dedifferentiated EC represents a high-grade endometrial carcinoma that requires extended surgery and indicates a poor prognosis. In cases with mismatch repair protein deficiency or POLE mutation, immuno-oncological treatment with checkpoint inhibitors are a therapeutic option.

[Morphology of secondary ovarian tumors and metastases]

The distinction between primary and secondary (metastatic) ovarian tumors is essential for the selection of appropriate surgical interventions, chemotherapeutic treatment and prognostic evaluation for the patient. Metastatic tumors of the ovary range between 5 % and 30 %. The majority of ovarian metastases in Europe and North America derive from colorectal (25-50 %) and breast cancers (8-25 %). A major issue is the differential diagnosis of mucinous tumors. Major features favoring metastasis include bilaterality, size < 10 cm, ovarian surface involvement, extensive intra-abdominal spread, and infiltrative growth within the ovary involving the corpus albicans and corpora lutea. An algorithm using bilaterality and tumor size (cut-off 10 cm) allows correct categorization in approximately  85 % of the cases. Although immunohistochemistry (especially CK7 and CK20 in mucinous tumors) using a panel of antibodies plays a valuable role and is paramount in the diagnosis, the results must be interpreted with caution and within the relevant clinical and histopathological context. It is necessary to note that the correct diagnosis of ovarian metastases always needs interdisciplinary and multidisciplinary approaches.

[New FIGO classification of ovarian, fallopian tube and primary peritoneal cancer]

During recent years paramount changes have occurred in the pathogenesis of ovarian cancer and recent clinical studies identified new prognostic factors. Consequently, the FIGO has established a new staging system collectively covering carcinomas derived from the ovaries, the fallopian tubes and primary peritoneal cancers as well as malignant ovarian germ cell and sex-cord stromal tumors. The new staging system started on 01 January 2014. Major changes occurred in the FIGO IC/T1c stage with surgical spill (FIGO IC1/T1c1) versus capsule ruptured before surgery or tumor on ovarian or fallopian tube surface (FIGO IC2/T1c2) versus malignant cells in the ascites or peritoneal washings (FIGO IC3/T1c3). The regional lymph node metastases were subcategorised using a cut-off value of 10 mm as the largest dimension of the metastatic deposits. Distant metastases (excluding peritoneal metastases) were substaged as FIGO IVA/M1a in cases of cytologically or histologically proven pleural involvement and as FIGO IVB/M1b in cases of parenchymal metastases and metastases in extra-abdominal organs (including lymph nodes outside the peritoneal cavity and the inguinal lymph nodes).

[HPV-associated alterations of the vulva and vagina. Morphology and molecular pathology]

Non-neoplastic HPV-induced alterations of the vulva and vagina are frequent. The traditional three-tier grading system of vulvar intraepithelial neoplasia (VIN) will be replaced by the definition of usual and simplex type of VIN. The usual type is characterized by a strong association to high-risk HPV infections, the occurrence at younger age and multifocality, mostly associated with non-keratinizing squamous cell carcinoma. The differentiated (or simplex) type is rare and shows an association to older age and p53 alterations and is typically diagnosed co-incidentally with keratinizing squamous cell carcinoma. Vaginal intraepithelial neoplasia (VAIN) is still graded into VAIN 1-3 where VAIN 1 and 2 are mostly associated with low-risk HPV infections and a high spontaneous regression rate whereas VAIN 3 represents a high-risk HPV-associated lesion with capable progression into (micro-)invasive carcinoma. The differential diagnosis between a non-neoplastic condylomatous lesion and VIN common type and VAIN may be aided by p16 immunohistochemistry. The HPV-associated invasive vulvo-vaginal cancers are verrucous carcinoma (low-risk HPV) and the high-risk HPV-induced (non-keratinizing) squamous cell carcinoma (NOS), the condylomatous (warty) carcinoma and the very rare vaginal squamo-transitional carcinoma.