Clinicopathologic Analysis of 138 Uterine Serous Carcinomas: Morphology Revisited

Serous carcinomas are copy-number-high (p53-abnormal) endometrial carcinomas with adverse outcomes. We aimed to assess the prognostic value of classic morphologic features in these tumors. Treatment-naive uterine serous carcinomas diagnosed from 1995 to 2022 were identified, and clinical-pathologic features were evaluated. The median age was 71 (52 to 95) years. Of 138 tumors, most (87 [63%]) were myoinvasive, and 51 (37%) were endometrium-confined, including 11 (21.6%) with only intraepithelial growth and 40 (78.4%) with stromal invasion within polyps and/or background endometrium. Predominant growth pattern was papillary in 63 tumors (45.6%), glandular in 60 (43.5%), and solid in 15 (10.9%). Lymphovascular invasion (LVI) was present in 49 (35.5%) cases, with nodal micro/macrometastases in 25/106 (23.6%) and isolated tumor cells in 3/106 (2.8%). Of 126 patients with follow-up (median: 38 mo, 0.9 to 230.7), 49 (38.9%) experienced recurrences and 27 (21.4%) died of disease. Both recurrence-free and disease-specific survival were associated with T category of pTNM staging, FIGO stage, endometrial stromal invasion, myoinvasion, margin status, cervical, lower uterine segment, and uterine serosal involvement (all P<0.0001), LVI (P≤0.002), predominant growth pattern, surrounding intraepithelial growth, and multinucleated tumor cells (P≤0.01). Patients with only intraepithelial growth experienced no recurrence or cancer-related death. LVI was associated with decreased recurrence-free (P<0.0001) and disease-specific (P<0.001) survival regardless of extent. T category (P=0.0049) and uterine serosal involvement (P=0.0514) were independent predictors of recurrence-free survival, with T category (P=0.03) also predicting disease-specific survival. The presence of only intraepithelial growth portends a favorable prognosis in serous carcinoma, whereas the clinical significance of the extent of LVI is limited.