Isolated axillary metastasis from early-stage dMMR endometrial carcinoma: a case report and mini-review

Axillary lymph node metastasis (ALNM) from endometrial carcinoma is extremely rare, particularly in tumors with early-stage, endometrioid histology. The clinical characteristics, underlying mechanisms, and optimal management strategies for this rare metastatic pattern remain insufficiently defined. We report a case of a 63-year-old woman diagnosed with FIGO 2023 stage IIB, grade 2 endometrioid endometrial carcinoma exhibiting mismatch repair deficiency (dMMR) and substantial lymphovascular space invasion (LVSI). She underwent surgery followed by adjuvant pelvic radiotherapy and vaginal brachytherapy. Approximately one year later, the patient developed isolated right axillary lymphadenopathy. Histopathological and immunohistochemical analyses confirmed metastatic endometrioid adenocarcinoma of uterine origin. The patient was treated with tislelizumab and lenvatinib but experienced progressive disease, with enlarging axillary nodes and new chest wall involvement. Salvage radiotherapy with a simultaneous integrated boost was administered and achieved tumor regression. A focused review of previously reported cases of axillary lymph node metastasis from endometrial carcinoma was conducted to summarize clinicopathologic features and treatment approaches. This case highlights an unusual metastatic pattern of endometrial cancer and underscores the need for individualized risk stratification, long-term surveillance, and timely integration of local therapy when systemic treatment proves insufficient.