Mediastinal cystic hygromas: CT characteristics and pathogenetic consideration

Area of Science:

• Thoracic imaging
• Diagnostic radiology
• Surgical pathology

Background:

• Mediastinal masses represent a diverse group of neoplastic and non-neoplastic conditions.
• Cystic hygromas (lymphatic malformations) are typically diagnosed in pediatric populations.
• Primary mediastinal cystic hygromas in adults are exceptionally rare, posing diagnostic challenges.

Observation:

• Two adult patients presented with asymptomatic primary mediastinal cystic hygromas.
• Computed Tomography (CT) was utilized for detailed imaging of the mediastinal masses.
• The lesions were located in the superior mediastinum, adjacent to the trachea and vertebrae.

Findings:

• CT revealed well-defined, round to oval masses with smooth, sharp outlines.
• Homogeneous low-attenuation density was observed, with no evidence of calcification.
• The masses caused mass effect, compressing adjacent mediastinal structures without gross invasion.

Implications:

• Characteristic CT findings can suggest a diagnosis of primary mediastinal cystic hygroma in adults.
• Non-invasive imaging may obviate the need for biopsy in select cases.
• Understanding these imaging features aids in differential diagnosis of superior mediastinal masses.