Benign, persistent, and invasive: mechanistic and translational approaches to middle‑ear cholesteatoma

Acquired middle-ear cholesteatoma is a histologically benign keratinizing squamous epithelial lesion that paradoxically exhibits locally destructive, recurrent, and invasive behavior, often resulting in ossicular erosion, hearing loss, labyrinthine fistula, and, rarely, intracranial complications. Surgical excision remains the primary management strategy; however, recurrence is common due to persistent microenvironmental drivers. Recent mechanistic studies—including single-cell transcriptomics, spatial proteomics, and epigenetic profiling—reveal a multifactorial pathogenesis orchestrated by chronic inflammation, proteolytic extracellular-matrix remodeling, osteoclast activation via RANKL and activin A, epithelial plasticity with partial epithelial-to-mesenchymal transition (EMT), and a dysbiotic, biofilm-forming microbiome. Emerging evidence further implicates oxidative stress, RNA and epigenetic modifications, miRNA dysregulation, and immune cell infiltration as central modulators of lesion chronicity and bone resorption. Collectively, these processes establish a self-sustaining pro-osteolytic microenvironment that drives bone erosion and postoperative recurrence. Cholesteatoma recapitulates several features of malignant lesions—hyperproliferation, local invasion, and stromal/immune cell recruitment—yet remains fundamentally benign, lacking metastatic potential and genomic instability. Its aggression is ecological rather than genetic, highlighting the potential for microenvironment-directed, precision-based strategies. Adjunctive approaches may include local delivery of modulatory agents, targeted interference with inflammatory, proteolytic, osteoclastogenic, and microbial axes, and biomarker-guided patient stratification. Preclinical and early-phase experimental studies assessing target engagement, radiologic stabilization, and molecular surrogates of efficacy could inform safer, mechanism-driven interventions that complement surgery, reduce recurrence, and preserve hearing. Integrating molecular pathobiology with clinical strategy positions cholesteatoma as a model for benign yet locally aggressive, microenvironment-driven disease, providing a roadmap for translational therapies with direct relevance to surgical practice.