Immature Teratoma of Uterine Origin: A Case Report and Literature Review.

Immature uterine teratoma is an extremely rare extragonadal germ cell tumour with only a small number of reported cases. Given its rarity, standardised treatment guidelines are unavailable, requiring an individualised management approach. Post-treatment assessment remains challenging, particularly in differentiating gliomatosis peritonei, a benign glial implant, from residual malignancy, as this can critically influence subsequent decisions regarding additional surgery or chemotherapy. A 44-year-old woman presented with prolonged genital bleeding and a vaginal mass that was initially suspected to be a prolapsing submucosal fibroid. Surgery confirmed a grade 3 immature teratoma with peritoneal dissemination and ovarian metastasis, necessitating four cycles of bleomycin, etoposide, and cisplatin chemotherapy. Post-treatment imaging suggested a residual tumour; however, a secondary laparotomy revealed gliomatosis peritonei. Treatment decisions were guided by a comprehensive analysis of International Germ Cell Consensus Classification (IGCCC) and modified IGCCC risk stratifications, existing guidelines for gonadal and extragonadal germ cell tumours, and a review of past cases. Although limited by a small number of cases and clinical heterogeneity, findings from previous reports, including the present case, suggest a potential role for adjuvant chemotherapy in reducing recurrence, regardless of the tumour stage. Notably, even after chemotherapy, assessment continues to pose diagnostic difficulties in differentiating residual immature teratomas from gliomatosis peritonei, often requiring surgical confirmation. Optimal management of immature uterine teratomas has yet to be defined. This case underscores the importance of multimodal therapy and precise post-treatment evaluation for recurrence and residual disease. Further case accumulation and collaborative research are crucial to refine treatment strategies and improve outcomes.