Mismatch Repair-Deficient FIGO Stage IA Endometrial Adenocarcinoma With Negative Nodal Biopsy Presenting as Isolated Orbital Metastasis.

Endometrial cancer is the most common malignancy of the female genital tract in the United States and the fourth most common cancer among women worldwide. Recently, the pathological classification of endometrial cancer has expanded from a two-tiered system to a four-group system based on molecular profiling. Typically, metastatic endometrial cancer spreads via the lymphatic system, most frequently to the retroperitoneum. Hematogenous spread is rare but can occur. We present a case of an 82-year-old female with a history of FIGO (International Federation of Gynecology and Obstetrics) stage IA endometrial adenocarcinoma, status post total hysterectomy and bilateral salpingo-oophorectomy, with negative lymph node biopsy, who later presented with eye swelling and pain. Imaging revealed metastatic disease to the orbit with invasion of the orbital roof. She subsequently underwent surgical resection, radiation, and systemic chemotherapy. Recurrence of grade IA endometrial carcinoma following hysterectomy and bilateral salpingo-oophorectomy with negative lymph node biopsies is exceedingly rare. The risk of pelvic lymph node involvement in stage IA disease is ≤3%, with a five-year progression-free survival rate of 95-98%. Current methods of metastatic assessment include lymphadenectomy and sentinel lymph node biopsy, although the optimal approach remains debated. This case underscores the need for continued advancements in risk stratification and early identification of patients with occult metastatic disease.