Granulomatous lobular mastitis: diagnostic and prognostic biomarkers

Granulomatous lobular mastitis (GLM) is a chronic, immune-mediated inflammatory breast disease of elusive etiology that presents formidable challenges in clinical management. This clinically oriented review synthesizes current evidence on biomarkers according to their potential applications in GLM diagnosis, differential diagnosis, disease-activity assessment, abscess prediction, recurrence surveillance, and treatment guidance. We critically evaluate conventional inflammatory indices, endocrine markers, immune-cell phenotypes, cytokines, complement-related markers, and emerging molecular signatures, while considering the influence of specimen type, disease stage, comparator population, and assay methodology on reported findings. Recent single-cell transcriptomic and metabolomic studies have expanded the biomarker landscape beyond circulating proteins, whereas epitranscriptomic regulation and immune-cell metabolic reprogramming remain emerging areas with limited direct GLM-specific evidence. Overall, routinely available markers such as CRP, ESR, NLR, SII, and prolactin currently offer the greatest clinical accessibility but limited disease specificity, whereas novel immune and molecular biomarkers remain largely exploratory. Future multicenter prospective studies integrating clinical, imaging, and molecular data are needed to develop robust biomarker panels and support precision management of GLM.