Contrast-enhanced CT images demonstrate a large mass located
within the anterior mediastinum, which extends inferiorly along the diaphragm
with mass effect on the anterior margin of the liver. The mass also extends
posteriorly along the inferior margin of the heart, a finding better appreciated
using the DICOM viewer. The mass contains a large amount of macroscopic fat
with intervening soft-tissue density. Numerous round calcifications with lucent
centers are present throughout the mass, consistent with phleboliths. Positron
emission tomography (PET)/CT images demonstrate that the mass demonstrates
minimal (FDG) uptake, similar to that of background. Multiple hilar lymph nodes with increased FDG uptake are
secondary to sarcoidosis.
Axial T2-weighted, T2-weighted with fat saturation,
T1-weighted precontrast, and T1-weighted postcontrast during the portal venous
phase and 20-min delayed images are provided. The mass is hyperintense on
T2-weighted images with loss of fat signal on fat-saturated images. After the
administration of intravenous contrast material, the mass demonstrates
progressive enhancement, most pronounced on delayed images. Rounded foci of
hypointensity are consistent with the phleboliths seen on the CT examination.
Hemangiomas are benign vascular tumors that rarely occur
within the mediastinum, accounting for <0.5% of all mediastinal masses. Most
patients are asymptomatic with the masses discovered incidentally. However,
some patients may experience symptoms due to mass effect on mediastinal structures,
such as the esophagus, trachea, and heart. Mediastinal hemangiomas are
typically found in young patients, most often <35 years of age. The anterior
mediastinum represents the most common mediastinal location, although
occurrences have been reported within the middle and posterior
Mediastinal hemangiomas are usually well defined, but lack a
capsule. Portions of the mass may insinuate between structures as in this case.
Histologically, hemangiomas consist of large, interconnecting vascular spaces
with various amounts of interspersed stromal elements, such as fat, myxoid, and
fibrous tissue. Based upon the size of the vascular spaces, they may be further
categorized as capillary, cavernous, or venous hemangiomas, with capillary and
venous forms representing over 90% of hemangiomas.
The imaging appearance of mediastinal hemangiomas is
typically nonspecific, revealing only an enhancing mass. The most
characteristic finding of mediastinal hemangiomas is the presence of
phleboliths, best seen by CT or plain radiographs. Phleboliths are reportedly
found in approximately 10% of mediastinal hemangiomas, but are virtually
diagnostic when present. Punctate calcifications are more common, but are a
nonspecific finding. While fatty components are common in soft-tissue
hemangiomas, they are rare in mediastinal hemangiomas. The pattern of contrast
enhancement varies between lesions, but is most often heterogenous and
progressive as with hemangiomas in other parts of the body. Magnetic resonance
imaging (MRI) of hemangiomas reveals hyperintense lesions on T2-weighted
images. In cases such as this one with a large fat component, T2-weighted
images with fat saturation often best demonstrate the high signal intensity of
the hemangiomas. If PET/CT is obtained due to the nonspecific imaging
appearance found on CT and MRI, hemangiomas will demonstrate low FDG uptake,
similar to background uptake.
Treatment of mediastinal hemangiomas consists of observation
if the diagnosis can be made preoperatively and the patient is asymptomatic. In
equivocal cases, surgical resection is often used for diagnostic and
therapeutic purposes, as transthoracic needle biopsy is often of little
- Sakurai K, Hara M, Ozawa Y, et al.
Thoracic hemangiomas: Imaging via CT, MR, and PET along with pathologic correlation.
J Thorac Imaging. 2008;23:114-120.
- Agarwal PP, Seely JM, Matzinger FR. Case
130: Mediastinal hemangioma. Radiology.
- McAdams HP, Rosado-de-Christenson ML,
Moran CA. Mediastinal hemangioma: Radiographic and CT features in 14 patients. Radiology. 1994;193:399-402.
- Abe K, Akata S, Ohkubo Y, et al. Venous hemangioma
of the mediastinum. Eur Radiol. 2001;11:73-75.