Radiologic-Pathologic
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Mediastinal S. Chew1
Felix
Conferences
included
and Ralph
liposarcoma,
diagnosis
surgical
was
resection
was
performed.
The
the frontal chest film. Because they are asymptomatic until marked mass effect occurs, thymolipomas often become large, sometimes weighing several kilograms at the time of excision. Thymolipomas are uncommon, accounting for approximately 5% of all thymic tumors. Most are discovered incidentally. In a very few cases, myasthenia gravis is a concurrent condition, but the association is weak and is probably coincidental [4]. When treated at all, the treatment is surgical resection. They do not recur.
Microscooy revealed mature tissue interspersed. The final
thymolipoma.
Thymolipomas are unusual benign mediastinal tumors composed of thymic and adipose tissue. The imaging characteristics are those of fat [1, 2], although the thymic tissue may appear as islands of softtissue density within the fat. Arising in the anterior mediastinum at the level of the thymus gland, these soft and pliable tumors droop inferiorly as they enlarge and are said to slump onto the diaphragm, accommodating themselves to the spaces between the lungs and the heart, diaphragm, or anterior mediastinum [3]. Their pendulous, elongated, teardrop shape leaves the anterior clear space unencumbered on the lateral chest film. They may simulate cardiomegaly on
REFERENCES 1. Faerber EN, Balsara AK, Shidlow DV, Marmon LM, Zaeri N. Thymolipoma: computed tomographic appearances. Pediatr Radio! 1990;20: 196-197 2. Shirkhoda A, Chasen MH, Eftekhari F, Goldman AM, Decaro LF. MR imaging of mediastinal thymolipoma. J ComputAsst Tomogr 1987;11 :364365 3. Teplick JG, Nedwich A, Haskin ME. Aoentgenographic features of thymolipoma. AJR 1973;1 17:873-877 4. Pan CH, Chiang CY, Chen SS. Thymolipoma in patients with myasthenia gravis: report of two cases and a review. Acta Neurol Scand 1988;78: 16-21
Fig. 1.-Mediastinal thymolipoma. A, Detail of chest radiograph shows an abnormal density (white arrows) projected over left pulmonary artery (black arrow). B, CT scan at level of aortic arch shows an anterior fatty mass (M) adjacent to thymus (arrow). C, CT scan at level of left pulmonary artery shows fatty mass (M) that showed as abnormal density on plain film (A). D, An encapsulated fatty mass with interspersed thymic tissue was found at surgery. Note pendulous, elongated, teardrop
From the weekly radiologic-pathologic correlation conferences conducted by Jack Wittenberg. Pathology Felix S. Chew, Daniel P. Barboriak, William E. Palmer, Daniel I. Rosenthal. ‘Both authors: Department of Radiology, Massachusetts General Hospital and Harvard Medical Schcol, requests to F. S. Chew. AJR 157:468,
September
Hospital
Weissleder
lesion was fatty and encapsulated. adipose tissue with normal thymic pathologic
General
Thymolipoma
An abnormality was found incidentally on the chest radiograph of a 49-year-old woman admitted for wrist surgery. The mediastinal contour was broad and had an abnormal density projected over the left pulmonary artery (Fig. 1). Chest CT showed a fatty mass adjacent to the thymus. The mass extended caudad along the ascending aorta and the left cardiac margin for 6 cm. The chest radiographs and CT scans were otherwise unremarkable. Because the differential diagnosis
of the Massachusetts
1991 0361 -803X/91/1573-0468
© American
Roentgen
Ray Society
editor:
Andrew
32 Fruit
St.,
shape.
E. Rosenberg. Boston,
Radiology
MA 02114.
Address
editors: reprint
Downloaded from www.ajronline.org by 117.255.255.101 on 10/20/15 from IP address 117.255.255.101. Copyright ARRS. For personal use only; all rights reserved
Mediastinal S. Chew1
Felix
Conferences
included
and Ralph
liposarcoma,
diagnosis
surgical
was
resection
was
performed.
The
the frontal chest film. Because they are asymptomatic until marked mass effect occurs, thymolipomas often become large, sometimes weighing several kilograms at the time of excision. Thymolipomas are uncommon, accounting for approximately 5% of all thymic tumors. Most are discovered incidentally. In a very few cases, myasthenia gravis is a concurrent condition, but the association is weak and is probably coincidental [4]. When treated at all, the treatment is surgical resection. They do not recur.
Microscooy revealed mature tissue interspersed. The final
thymolipoma.
Thymolipomas are unusual benign mediastinal tumors composed of thymic and adipose tissue. The imaging characteristics are those of fat [1, 2], although the thymic tissue may appear as islands of softtissue density within the fat. Arising in the anterior mediastinum at the level of the thymus gland, these soft and pliable tumors droop inferiorly as they enlarge and are said to slump onto the diaphragm, accommodating themselves to the spaces between the lungs and the heart, diaphragm, or anterior mediastinum [3]. Their pendulous, elongated, teardrop shape leaves the anterior clear space unencumbered on the lateral chest film. They may simulate cardiomegaly on
REFERENCES 1. Faerber EN, Balsara AK, Shidlow DV, Marmon LM, Zaeri N. Thymolipoma: computed tomographic appearances. Pediatr Radio! 1990;20: 196-197 2. Shirkhoda A, Chasen MH, Eftekhari F, Goldman AM, Decaro LF. MR imaging of mediastinal thymolipoma. J ComputAsst Tomogr 1987;11 :364365 3. Teplick JG, Nedwich A, Haskin ME. Aoentgenographic features of thymolipoma. AJR 1973;1 17:873-877 4. Pan CH, Chiang CY, Chen SS. Thymolipoma in patients with myasthenia gravis: report of two cases and a review. Acta Neurol Scand 1988;78: 16-21
Fig. 1.-Mediastinal thymolipoma. A, Detail of chest radiograph shows an abnormal density (white arrows) projected over left pulmonary artery (black arrow). B, CT scan at level of aortic arch shows an anterior fatty mass (M) adjacent to thymus (arrow). C, CT scan at level of left pulmonary artery shows fatty mass (M) that showed as abnormal density on plain film (A). D, An encapsulated fatty mass with interspersed thymic tissue was found at surgery. Note pendulous, elongated, teardrop
From the weekly radiologic-pathologic correlation conferences conducted by Jack Wittenberg. Pathology Felix S. Chew, Daniel P. Barboriak, William E. Palmer, Daniel I. Rosenthal. ‘Both authors: Department of Radiology, Massachusetts General Hospital and Harvard Medical Schcol, requests to F. S. Chew. AJR 157:468,
September
Hospital
Weissleder
lesion was fatty and encapsulated. adipose tissue with normal thymic pathologic
General
Thymolipoma
An abnormality was found incidentally on the chest radiograph of a 49-year-old woman admitted for wrist surgery. The mediastinal contour was broad and had an abnormal density projected over the left pulmonary artery (Fig. 1). Chest CT showed a fatty mass adjacent to the thymus. The mass extended caudad along the ascending aorta and the left cardiac margin for 6 cm. The chest radiographs and CT scans were otherwise unremarkable. Because the differential diagnosis
of the Massachusetts
1991 0361 -803X/91/1573-0468
© American
Roentgen
Ray Society
editor:
Andrew
32 Fruit
St.,
shape.
E. Rosenberg. Boston,
Radiology
MA 02114.
Address
editors: reprint
