Unilateral Nodular Adrenal Hyperplasia Mimicking Endometrial Cancer Metastasis on 18F-FDG PET/CT After Immunochemotherapy

Unilateral nodular adrenal hyperplasia after immunochemotherapy is extremely rare. We reported a 70-year-old woman with endometrial cancer who underwent ¹⁸F-FDG PET/CT to evaluate the immunochemotherapy response. Compared with the baseline, follow-up PET/CT revealed a newly hypermetabolic nodule in the left adrenal gland, initially suspected to be metastatic. However, surgical resection and pathology confirmed it as adrenal hyperplasia. This case highlights the importance of recognizing unilateral nodular adrenal hyperplasia as a rare imaging finding mimicking metastasis following immunochemotherapy, which should be considered in the differential diagnosis.