Nasal immature teratoma in an elderly patient: Clinicopathological and epigenetic analogies with central nervous system counterparts, alongside genomic divergences.

Germ cell tumors (GCTs) are categorized as gonadal or extra-gonadal, based on the origin. Extra-gonadal GCTs predominantly manifest within the central nervous system (CNS), mediastinum, retroperitoneum, and sacrococcygeal region. These malignancies are most frequently diagnosed in the pediatric, adolescent, and young adult demographics. Incidences of GCT within the nasal cavity are notably scarce, with only six cases documented. This report details the case of a 70-year-old man who presented with a left nasal mass ultimately diagnosed as immature teratoma. A remarkable aspect of this case was the detection of SMARCA4 (BRG1) loss through immunohistochemical analysis. In addition, methylation profiling aligned this case with CNS GCTs, specifically those classified as non-germinomatous GCTs. This molecular characterization informed a tailored therapeutic strategy incorporating carboplatin and etoposide, alongside localized irradiation. This individualized treatment regimen achieved favorable outcomes, with the patient remaining recurrence free for over three years. This highlights the need for precise therapeutic approaches in the management of extragonadal GCTs, particularly those arising in atypical anatomical locations. The present case accentuates the significance of thorough diagnostic evaluations and customized treatment plans for rare GCT presentations. Further empirical and clinical investigations are warranted to enhance our understanding of and refine therapeutic protocols for such exceptional cases.