## Histological Types of Epithelial Ovarian Cancer **Key Point:** Serous cystadenocarcinoma accounts for approximately 40–50% of all epithelial ovarian cancers, making it the most common histological variant encountered in clinical practice. ### Distribution of Epithelial Ovarian Cancer Subtypes | Histological Type | Frequency (%) | Key Features | |---|---|---| | Serous | 40–50 | Most common; often high-grade; aggressive; poor prognosis | | Mucinous | 10–15 | Lower frequency; often presents at advanced stage; worse prognosis than serous | | Endometrioid | 10–15 | Associated with endometriosis; often early-stage at diagnosis | | Clear cell | 5–10 | Rare; associated with endometriosis; chemotherapy-resistant | | Brenner | 2–5 | Rare; usually low-grade; excellent prognosis | **High-Yield:** Serous tumors are the most frequently encountered type in both benign (serous cystadenoma) and malignant (serous cystadenocarcinoma) settings. High-grade serous ovarian cancer (HGSOC) is particularly aggressive and accounts for the majority of ovarian cancer deaths [cite:Robbins 10e Ch 22]. ### Clinical Significance **Clinical Pearl:** Serous cystadenocarcinomas typically present at advanced stages (Stage III–IV) because of their aggressive nature and the lack of early symptoms. They are highly chemosensitive to platinum-based regimens, making platinum-taxane combination therapy the standard of care. **Mnemonic:** **SMECB** — Serous (most common), Mucinous, Endometrioid, Clear cell, Brenner (in order of decreasing frequency among epithelial types).
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