Surface epithelial-stromal tumors are a class of ovarian neoplasms that may be benign or malignant. Neoplasms in this group are thought to be derived from the ovarian surface epithelium (modified peritoneum) or from ectopic endometrial or fallopian tube (tubal) tissue. Tumors of this type are also called ovarian adenocarcinoma. This group of tumors accounts for 90% to 95% of all cases of ovarian cancer; however is mainly only found in postmenopausal women with the exception of the United States where 7% of cases occur in women under the age of 40. Serum CA-125 is often elevated but is only 50% accurate so it is not a useful tumor marker to assess the progress of treatment. 75% of women with epithelial ovarian cancer are found within the advanced-stages; however younger patients are more likely to have better prognoses than older patients.
Classification
thumb|300px|[[Ovarian tumors by incidence and risk of ovarian cancer, with surface epithelial-stromal tumors at top.]]
thumb|300px|Ovarian cancers in women aged 20+, with area representing relative incidence and color representing [[5-year relative survival rate.
Prognosis
The prognosis of a serous tumor, like most neoplasms, depends on
- degree of differentiation
- this is how closely the tumor cells resemble benign cells
- a well-differentiated tumor closely resembles benign tumors
- a poorly differentiated tumor may not resemble the cell type of origin at all
- a moderately differentiated tumor usually resembles the cell type of origin, but appears frankly malignant
- extension of tumor to other structures
- in particular with serous malignancies, the presence of malignant spread to the peritoneum is important with regard to prognosis.
The five-year survival rate of borderline tumors and malignant tumors confined to the ovaries are 100% and 70% respectively. If the peritoneum is involved, these rates become 90% and 25%.
While the 5-year survival rates of borderline tumors are excellent, this should not be seen as evidence of cure, as recurrences can occur many years later.
Mucinous tumors
thumb|Histopathology of lining of a benign mucinous tumor of the ovary. Benign mucinous ovarian tumors consist of simple, nonstratified columnar epithelium with basally-located hyperchromatic nuclei and resemble gastric foveolar epithelium.
Mucinous tumors:
- Closely resemble their serous counterparts but unlikely to be bilateral
- Somewhat less common, accounting for about 25% of all ovarian neoplasms
- In some cases mucinous tumors are characterized by more cysts of variable size and a rarity of surface involvement as compared to serous tumors
- Also in comparison to serous tumors, mucinous tumors are less frequently bilateral, approximately 5% of primary mucinous tumors are bilateral.
- May form very large cystic masses, with recorded weights exceeding 25 kg
Pathology
Mucinous tumors are characterized by a lining of tall columnar epithelial cells with apical mucin and the absence of cilia, similar in appearance with benign cervical or intestinal epithelia. The appearance can look similar to colonic or ovarian cancer, but typically originates from the appendix (see mucinous adenocarcinoma with clinical condition Pseudomyxoma peritonei). Clear stromal invasion is used to differentiate borderline tumors from malignant tumors.
Prognosis
10-year survival rates for borderline tumors contained within the ovary, malignant tumors without invasion, and invasive malignant tumors are greater than 95%, 90%, and 66%, respectively. One rare but noteworthy condition associated with mucinous ovarian neoplasms is pseudomyxoma peritonei. As primary ovarian mucinous tumors are usually unilateral (in one ovary), the presentation of bilateral mucinous tumors requires exclusion of a non-ovarian origin, usually the appendix.
Endometrioid tumors
Endometrioid tumors account for approximately 20% of all ovarian cancers and are mostly malignant (endometrioid carcinomas). They are made of tubular glands bearing a close resemblance to benign or malignant endometrium. 15-30% of endometrioid carcinomas occur in individuals with carcinoma of the endometrium, and these patients have a better prognosis. They appear similar to other surface epithelial-stromal tumors, with solid and cystic areas. 40% of these tumors are bilateral, when bilateral, metastases is often present.
Pathology
- Glands bearing a strong resemblance to endometrial-type glands
- Benign tumors have mature-appearing glands in a fibrous stroma
- Borderline tumors have a complex branching pattern without stromal invasion
- Carcinomas (malignant tumors) have invasive glands with crowded, atypical cells, frequent mitoses. With poorer differentiation, the tumor becomes more solid.
Prognosis
Prognosis again is dependent on the spread of the tumor, as well as how differentiated the tumor appears. The overall prognosis is somewhat worse than for serous or mucinous tumors, and the 5-year survival rate for patients with tumors confined to the ovary is approximately 75%.
Clear cell tumors
thumb|right|[[Micrograph of an ovarian clear cell carcinoma. H&E stain.]]
Clear cell tumors are characterized by large epithelial cells with abundant clear cytoplasm and may be seen in association with endometriosis or endometrioid carcinoma of the ovary, bearing a resemblance to clear cell carcinoma of the endometrium. They may be predominantly solid or cystic. If solid, the clear cells tend to be arranged in sheets or tubules. In the cystic variety, the neoplastic cells make up the cyst lining.
Prognosis
These tumors tend to be aggressive, the five year survival rate for tumors confined to the ovaries is approximately 65%. If the tumor has spread beyond the ovary at diagnosis, the prognosis is poor
Brenner tumor
thumb|right|[[Brenner tumour. H&E stain.]]
Brenner tumors are uncommon surface-epithelial stromal cell tumors in which the epithelial cell (which defines these tumors) is a transitional cell. These are similar in appearance to bladder epithelia. The tumors may be very small to very large, and may be solid or cystic. Histologically, the tumor consists of nests of the aforementioned transitional cells within surrounding tissue that resembles normal ovary. Brenner tumors may be benign or malignant, depending on whether the tumor cells invade the surrounding tissue.
Small cell tumors
Small cell ovarian cancer (SCCO) are generally classified into epithelial tumors associated with distinctive endocrine features.
The World Health Organisation (WHO) recognises SCCO as two distinct entities: Small Cell Ovarian Cancer of Hypercalcemic Type (SCCOHT) and Small Cell Ovarian Cancer of Pulmonary Type (SCCOPT). It typically present with a unilateral large tumor. In people with platinum-sensitive relapsed EOC, research has found that Pegylated Liposomal Doxorubicin with Carboplatin is a better treatment than Paclitaxel with Carboplatin.
For advanced cancer of this histology, the US National Cancer Institute recommends a method of chemotherapy that combines intravenous (IV) and intraperitoneal (IP) administration. Preferred chemotherapeutic agents include a platinum drug with a taxane.
Metastases
For surface epithelial-stromal tumors, the most common sites of metastasis are the pleural cavity (33%), the liver (26%), and the lungs (3%).
Effect on fertility
Fertility subsequent to treatment of surface epithelial-stromal tumors depends mainly on histology and initial
staging to separate it into early borderline (or more benign) versus advanced stages of borderline (or more malignant). Conservative management (without bilateral oophorectomy) of early stage borderline tumors have been estimated to result in chance of over 50% of spontaneous pregnancy with a low risk of lethal recurrence of the tumor (0.5%).