## Histological Types of Epithelial Ovarian Cancer **Key Point:** Serous cystadenocarcinoma is the most common histological subtype of epithelial ovarian cancer, accounting for approximately 40–50% of all cases. ### Epidemiology of Epithelial Ovarian Cancer Subtypes | Histological Type | Frequency | Key Features | |---|---|---| | **Serous** | 40–50% | Most common; often presents at advanced stage; better prognosis than mucinous | | **Mucinous** | 10–15% | Second most common; often stage I at diagnosis; lower mortality | | **Endometrioid** | 10% | Associated with endometriosis; better prognosis | | **Clear cell** | 5–10% | Associated with endometriosis; chemotherapy-resistant | | **Brenner** | <5% | Rare; often benign or borderline | **High-Yield:** Serous tumors are not only the most common but also the most likely to present at **advanced stage (III–IV)** due to their aggressive biology and tendency for peritoneal spread. This contrasts with mucinous tumors, which are often diagnosed at stage I. ### Clinical Significance **Clinical Pearl:** Although serous cystadenocarcinoma is the most frequent type overall, **mucinous tumors have a better prognosis when stage-matched** because they typically present at earlier stages. The worse outcomes for serous tumors reflect their advanced presentation rather than inherent biological superiority of mucinous variants. **Mnemonic:** **SMECB** — Serous, Mucinous, Endometrioid, Clear cell, Brenner (in order of decreasing frequency among epithelial subtypes). [cite:Robbins 10e Ch 22]
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