Abstract
BACKGROUND: Eosinophilic adenoma, a benign tumor characterized by eosinophilic cell proliferation, typically arises in endocrine organs such as the thyroid or parathyroid glands. Ectopic parathyroid eosinophilic adenoma is rare and may mimic other mediastinal pathologies, leading to diagnostic challenges. CASE PRESENTATION: We present a case of a 54-year-old woman with a one-year history of dysphagia. Initial imaging and endoscopic studies suggested an esophageal stromal tumor. Thoracoscopic resection revealed a posterior mediastinal mass, later confirmed as an ectopic parathyroid eosinophilic adenoma through histopathological and immunohistochemical analysis. CONCLUSIONS: This case underscores the importance of integrating imaging, laboratory tests, and histopathology for accurate diagnosis of mediastinal masses. Minimally invasive thoracoscopic surgery proved effective for resection, highlighting the need for tailored therapeutic approaches. In order to avoid such misdiagnosis, clinicians should make a definite pathological diagnosis before surgery as much as possible.