Imaging of Cystic Masses of the Mediastinum

Abstract

Cystic masses of the mediastinum are well-marginated round lesions that contain fluid and are lined with epithelium. Major cystic masses include congenital benign cysts (ie, bronchogenic, esophageal duplication, neurenteric, pericardial, and thymic cysts), meningocele, mature cystic teratoma, and lymphangioma. Many tumors (eg, thymomas, Hodgkin disease, germ cell tumors, mediastinal carcinomas, metastases to lymph nodes, nerve root tumors) can undergo cystic degeneration-especially after radiation therapy or chemotherapy-and demonstrate mixed solid and cystic elements at computed tomography (CT) or magnetic resonance (MR) imaging. If degeneration is extensive, such tumors may be virtually indistinguishable from congenital cysts. A mediastinal abscess or pancreatic pseudocyst also appears as a fluid-containing mediastinal cystic mass. However, clinical history and manifestations, anatomic position, and certain details seen at CT or MR imaging allow correct diagnosis in many cases. Familiarity with the radiologic features of mediastinal cystic masses facilitates accurate diagnosis, differentiation from other cystlike lesions, and, thus, optimal patient treatment.

Computed tomography and magnetic resonance imaging of mediastinal tumors

“…Bronchogenic cysts are typically stable in size or may enlarge over years. An abrupt increase in size indicates hemorrhage or infection (58) and may result in rupture of the cyst.…”

Prenatal detection and evaluation of an extralobar pulmonary sequestration in the posterior mediastinum

“…Ectopic gastric mucosa within these cysts may cause hemorrhage, and the resulting debris yields intermediate echogenicity on ultrasonography. However through transmission of the beam is usually seen posterior to the mass, indicating its fluid nature 12 .…”

Imaging the posterior mediastinum: a multimodality approach

“…CT confirms a sharply defined, homogeneous, low-attenuation lesion up to 15 cm in diameter (25). The lesion protrudes from the spinal canal into the posterior mediastinum and has a right side predominance, possibly related to the aorta in the left side (24).…”

“…The lesion protrudes from the spinal canal into the posterior mediastinum and has a right side predominance, possibly related to the aorta in the left side (24). CT also reveals abnormalities in adjacent vertebrae and enlargement of intervertebral foramina (25). On MRI, meningoceles are cystic masses with signal intensity of cerebrospinal fluid.…”