Anterior mediastinal leiomyosarcoma mimicking thymoma: A case report.

RATIONALE: Mediastinal leiomyosarcoma is very rare. In this paper, we report one case of anterior mediastinal leiomyosarcoma and retrospectively review the imaging findings of previously reported cases.

PATIENT CONCERNS: A 61-year-old male patient was admitted to our hospital due to the presence of a mediastinal space-occupying lesion for two years. Two years previously, chest computed tomography (CT) showed a small nodule in the anterior mediastinum. Twenty days previously, the CT examination was repeated at the local hospital due to respiratory symptoms, which showed a mass in the anterior mediastinum and interstitial inflammation of both lungs. After admission to our hospital, chest contrast-enhanced CT scanning showed a mass in the right anterior mediastinum that was approximately 3.3 × 5.2 cm2 in size that had a clear boundary, slightly heterogeneous internal density and heterogeneous enhancement.

INTERVENTIONS: The patient underwent a mediastinal lump resection.

DIAGNOSES: Finally, the pathological diagnosis was anterior mediastinal leiomyosarcoma.

OUTCOMES: The patient recovered well after the operation.

LESSONS: Accidental discovery of anterior mediastinal nodules should be followed up. Mediastinal leiomyosarcoma is common in the posterior mediastinum. Imaging shows a heterogeneous mass with a space-occupying effect that may easily involve adjacent mediastinal vessels or infiltrate surrounding organs.