Breast, gynecologic and genitourinary morphology
Distinguish architecture, lineage and extent
A breast, gynecologic or genitourinary diagnosis integrates growth pattern, cell features, supporting structures and appropriate ancillary findings. Lobular and ductal breast patterns can differ in cohesion and E-cadherin expression, but a single stain is not an unconditional replacement for morphology. A myoepithelial layer contributes to assessing selected in situ and invasive differentials, with attention to the limitations of each marker and lesion. Benign fibroepithelial, in situ epithelial and invasive lesions cannot be separated solely by patient age or whether a palpable mass is mobile.
Apply the actual biomarker framework
Breast hormone-receptor and HER2 assessment requires valid controls, appropriate scoring and attention to preanalytical handling. Equivocal HER2 staining can require the relevant in situ hybridization pathway. A low-positive hormone-receptor result has a reporting and clinical context different from a uniformly strong positive tumor. A predictive assay validated in a particular receptor and disease setting cannot automatically be extended to every subtype. Molecular classification can contribute to endometrial assessment, but a pathogenic defining alteration must be distinguished from an uncertain variant.
Cervical and adnexal interpretation
Cervical cytology, histology and management algorithms answer related but distinct questions. Koilocytosis, high-grade squamous atypia, glandular abnormalities and infection-related changes require the relevant terminology and adequacy assessment. Cytology can raise concern for invasion but cannot independently establish the complete stromal relationship. The cervical Bethesda terminology must not be confused with the edition history of thyroid Bethesda reporting. Ovarian serous, mucinous, germ-cell and sex-cord stromal tumors have different morphological and molecular patterns. An immunophenotype contributes to identifying a Müllerian origin but is not the only evidence for a primary site.
Urologic sampling and stage
Renal tumors can share clear or eosinophilic cell appearances, requiring the actual architecture and a suitable panel. Prostatic carcinoma assessment considers infiltration, cytology, basal-cell evidence and the applicable grading system. In a bladder resection, lamina-propria invasion establishes at least that sampled extent; missing detrusor muscle does not prove that deeper invasion is absent elsewhere. Thick muscle bundles and ancillary stains are interpreted with specimen orientation and known limitations. Urinary cytology is especially useful for high-grade disease and has limited sensitivity for low-grade neoplasia. A reactive or virus-associated appearance must be distinguished from carcinoma without assuming the two processes cannot coexist.