We describe the architectural patterns of advanced ovarian/pelvic high-grade serous
carcinomas that have been treated with upfront surgery, followed by
adjuvant chemotherapy or
neoadjuvant chemotherapy, followed by interval debulking to explore the association with the chemotherapeutic response. For 70 cases of advanced (i.e. stage III/IV) high-grade serous
carcinomas (33
platinum resistant/intermediate, 37
platinum sensitive; 24 neoadjuvantly treated, 44 primary surgery), all
tumor-containing histologic slides were reviewed by 1 of 3 pathologists. Histologic type was confirmed and the following features were assessed: major architectural pattern and the presence of any of 8 predefined minor architectural patterns (papillary,
transitional cell carcinoma-like, micropapillary, microcystic, nested papillary, slit-like, glandular, solid). A semiquantitative assessment of psammoma bodies, histiocytic response,
necrosis, nuclear atypia, and single-cell invasion was performed. Mitotic count was performed in 10 HPF and 1 HPF was counted for intraepithelial lymphocytes. The morphologic features were tested for an association with previous
neoadjuvant chemotherapy and response to
chemotherapy (resistant/intermediate versus
chemotherapy-sensitive cases stratified by
neoadjuvant chemotherapy), which was carried out using χ tests for categorical variables and analysis of variance for continuous data. Combinations of features were analyzed using unsupervised clustering (Wald). Although 8 of 18 features were significantly different when samples from neoadjuvantly treated patients were compared with those not previously treated, no individual histomorphologic feature or a combination of features was associated with response to
chemotherapy. Further subtyping of high-grade serous
carcinomas will likely need ancillary molecular markers that may have a greater potential to identify cases that will not respond to
platinum-based
chemotherapy.