Clinical history: 50 year-old female with unilateral complex cystic mass in the right ovary measuring 25.0cm in maximum dimension.
What is the most probable diagnosis?
Borderline mucinous carcinoma with intraepithelial carcinoma
Ovary mucinous tumours are the second most frequent epithelial tumor after serous representing ~15% of ovarian neoplasms. They usually present in middle aged adults, pre-menopausal. 80% are benign, 10% are borderline and 10% are carcinoma. The majority (77%) of ovarian mucinous carcinomas are metastases, so it is important to rule these out.
Grossly they are usually unilateral, very cystic and present as very large masses (>10cm). They usually have a smooth outer surface with variable solid areas and are filled with sticky, gelatinous fluid rich in glycoproteins
Histologically the mucin producing cells can resemble endocervical, gastric, or intestinal type epithelium.
This case was a multilocular tumour that contained an atypical glandular cell proliferation with most areas lined with single layer of mucinous cells whereas the other areas show pseudostratified epithelium with frequent tufting. Approximately 30% of the tumour demonstrated a cribiform architecture with elongated fibrovascular cores along the stroma of the cysts consistent with the findings of intraepithelial carcinoma.
According to Khunamornpong et al. (International J Gynaecol Pathol., 2011; 30 :218-230) Stage 1C and greater mucinous borderline tumours that harbour more than 10% intraepithelial carcinoma component have significantly higher recurrence rate (>10%). However, an increment up to 80% of tumour with intraepithelial carcinoma showed only a slight increase in recurrence.
The entire appendix was submitted for microscopic examination and had no evidence of dysplasia or malignancy. No history of carcinoma elsewhere.