[A case of thymoma with thymic cyst]

Area of Science:

• Thoracic Surgery
• Pathology
• Oncology

Background:

• Thymoma is a rare tumor originating from the thymus gland.
• Thymic cysts are uncommon congenital or acquired lesions.
• Co-occurrence of thymoma and thymic cyst is exceptionally rare.

Observation:

• A 43-year-old male presented with an abnormal chest X-ray.
• Chest CT revealed a mediastinal mass and a cyst.
• Surgical exploration identified a capsulated thymoma and a multilocular thymic cyst.

Findings:

• Histological examination confirmed a mixed-type thymoma adjacent to a thymic cyst.
• Elevated levels of parathyroid hormone (PTH) and cancer antigen 19-9 (CA19-9) were detected in the cystic fluid.
• Clear separation between the thymoma and the thymic cyst was observed.

Implications:

• This case highlights the importance of considering thymic cysts in the differential diagnosis of mediastinal masses, even in the presence of thymoma.
• The elevated PTH and CA19-9 in the cyst fluid warrant further investigation into their potential role in thymic cyst pathogenesis.
• Further research is needed to understand the relationship between thymoma and thymic cysts and their clinical significance.