Beyond the Globe: Molecular Diagnostics of Optic Nerve, Orbital, and Adnexal Neoplasms

Recent advances in molecular pathology have transformed the diagnostic landscape and management of human cancer. Increasingly, integration of genomic and epigenomic data with conventional histopathology has improved tumor classification, refined prognostic assessment, and revealed previously unsuspected therapeutic targets. High-throughput techniques such as next-generation sequencing, gene fusion panels, and methylation arrays have expanded applicability to formalin-fixed tissue and enabled simultaneous evaluation of multiple cancer-defining alterations/genetic drivers. In optic nerve gliomas, MAPK pathway activation through BRAF or FGFR1 alterations, or NF1 inactivation, is a basic biological feature with diagnostic implications, while MEK inhibitors may be of clinical benefit in selected patients. Optic nerve sheath/orbital meningiomas demonstrate divergent molecular landscapes depending on location, with NF2-driven and non-NF2-driven pathways informing recurrence risk and behavior. In the orbit, characteristic genetic drivers facilitate diagnosis of mesenchymal tumors such as solitary fibrous tumor (NAB2::STAT6) and alveolar rhabdomyosarcoma (PAX3/7::FOXO1), while molecular profiling assists in distinguishing challenging peripheral nerve and melanocytic lesions. Similarly, lacrimal gland neoplasms parallel salivary gland counterparts, with recurrent fusions such as PLAG1, HMGA2, and MYB::NFIB of great diagnostic utility. These advances underscore the growing role of molecular diagnostics in improving accuracy, guiding prognostication, and refining the classification of rare ocular tumors. As high-throughput techniques continue to mature, integration with evolving spatial and single-cell-based approaches promises to expand our understanding and further personalize diagnostic and therapeutic strategies.