Chapter 1: Histopathology of gynaecological cancers
Chapter Authors:
B. Davidson, Department of Pathology, Oslo University Hospital, Norwegian Radium Hospital, Oslo; University of Oslo, Faculty of Medicine, Institute of Clinical Medicine, Oslo, Norway
S. Carinelli, Division of Gynecologic Oncology and Pathology, European Institute of Oncology (IEO), Milan, Italy
Tubo-ovarian tumours – Classification and germ cell tumours (GCTs)
Classification: female adnexal tumours consist of epithelial tumours (most common), sex cord-stromal tumours (SCSTs) and GCTs, as well as metastases.
Tumours are further classified as benign, low-grade malignant or fully malignant, with the majority of the latter being epithelial (carcinomas).
Ovarian cancer is a heterogeneous group of tumours; globally, it ranks eighth in terms of incidence and mortality among women (Figure 1.1).
Figure 1.1: Ovarian cancer incidence, GLOBOCAN 2020
Credit: Ferlay J, et al. Global Cancer Observatory: Cancer Today. International Agency for Research on Cancer, 2020; Available from: https://gco.iarc.fr/today, accessed [24 May 2024]
The majority of GCTs are unilateral tumours diagnosed in young women. The most common is mature teratoma, which accounts for 20% of ovarian tumours.
Mature teratomas often contain all three germ layers, though monodermal forms exist, e.g. struma ovarii, which consists of thyroid tissue (Figure 1.2).
Figure 1.2: Mature teratoma
Credit: Courtesy of the Authors
Mature teratomas should be adequately sampled to rule out an immature component or malignant tumour of somatic type.
Malignant GCTs consist of dysgerminoma, yolk sac tumour, immature teratoma, embryonal carcinoma and choriocarcinoma, or mixed forms.
Immunostains used in diagnosis include stem cell markers (SOX2, SALL4, OCT3/4), alpha-foetoprotein (AFP), human chorionic gonadotropin (hCG) and c-Kit (Figure 1.3).
Figure 1.3: Immature teratoma and dysgerminoma
Credit: Courtesy of the Authors
Chromosome 12 abnormalities and KIT mutation or amplification are seen in dysgerminoma but are not used in the diagnostic setting.
Revision Questions
- How are female adnexal tumours classified?
- Are the majority of GCTs in females benign or malignant?
- What types of malignant GCT are recognised?
