The value of hysteroscopic microvascular and morphological subclassification in diagnosing endometrial malignant lesions: A single‐center retrospective study

OBJECTIVE: This study develops and validates an integrated assessment system based on hysteroscopic features of microvascular morphology, lesion appearance, and extent, aiming to standardize the observational protocol and provide auxiliary judgment for diagnosing endometrial malignant lesions, especially for less experienced practitioners. METHODS: Data from 168 patients who underwent hysteroscopy with initial suspicion of endometrial malignant lesions at Hubei Maternal and Child Health Hospital from March 2020 to June 2021 were retrospectively analyzed. Hysteroscopic findings were systematically recorded according to lesion extent (localized/diffuse), microvascular classification (Type I-IV), morphological type (polypoid, nodular, papillary, ulcerative, hyperplastic), and the presence of necrosis or calcification. Biopsies were taken from suspicious areas for pathological examination. Using histopathology as the gold standard, the diagnostic performance of each indicator was evaluated. RESULTS: First, microvascular classification showed a significant correlation with lesion malignancy: Types I-II were most frequent in the hyperplasia without atypia group (68.6%), Type III was most frequent in the atypical hyperplasia group (54.9%), and Type IV was most frequent in the endometrial cancer group (48.4%). Second, among morphological types, the papillary pattern had the highest occurrence in the endometrial cancer group (58.1%) and, together with Type IV vessels, was significantly associated with malignant lesions (P < 0.001). Third, the proportion of postmenopausal patients in the endometrial cancer group was 64.5%, significantly higher than that in the benign group (P < 0.01). Fourth, a diagnostic model combining microvascular classification, lesion extent, and morphological type demonstrated excellent predictive value, with an AUC of 0.950 (95% CI: 0.912-0.989), a sensitivity of 87.1%, and a specificity of 84.7%. Finally, in this study, the under-diagnosis rate was 3.6%, and the over-diagnosis rate was 8.9%. CONCLUSION: The hysteroscopic microvascular and morphological classification system aids in distinguishing between benign and malignant endometrial lesions. Specifically, a papillary appearance and Type IV vessels are important indicators suggestive of malignancy. Combining multiple indicators improves diagnostic accuracy and can serve as an auxiliary tool for hysteroscopists, particularly for beginners.