Giant Anterior Mediastinal Hamartoma in a Middle-Aged Woman: A Rare Encounter.

Hamartomas are benign neoplasms most commonly arising in the lung, typically identified as incidental solitary pulmonary nodules. Occurrence in the mediastinum is exceedingly rare. Because anterior mediastinal lesions are most often malignant, hamartomas in this location pose a diagnostic challenge. We present the case of a 53-year-old female with a background of endometrial carcinoma who was evaluated for chest pain and palpitations. A chest radiograph revealed a large opacity in the left upper hemithorax, corresponding to a well-circumscribed anterior mediastinal mass on computed tomography. The lesion measured 7.7 × 7 × 7 cm, contained macroscopic fat, and partially compressed adjacent bronchovascular structures. A CT-guided biopsy demonstrated fibrous, cartilaginous, adipose, and bronchial elements without atypia, confirming the diagnosis of mediastinal hamartoma. Due to the lesion's size and compressive effects, surgical excision was performed through a left exploratory thoracotomy. The patient recovered well postoperatively. Mediastinal hamartomas are rare and can mimic more aggressive anterior mediastinal neoplasms. Imaging features such as fat density may suggest the diagnosis, but histopathology remains essential for confirmation. Surgical resection is indicated in symptomatic or compressive cases, and the prognosis following excision is excellent. This case highlights the importance of considering benign entities such as hamartoma in the differential diagnosis of anterior mediastinal masses.