RADIOGRAPHIC EXHIBIT Although some suggest that fatty tissue may on occasion be recognized within the mediastinum (4), a review of the literature failed to yield a similar case. In those cases of lipoma in which chest radiographs were either reproduced or described, a mediastinal lesion of soft-tissue density was invariably reported (1,3,6-8, 10, 11).

Radiolucent Mediastinal Lipoma 1 Edwin S. Wilson, M.D. Intrathoracic lipomas are rare. A patient with a surgically proved mediastinal lipoma is described. The lesion presented as an asymptomatic radiolucent mass within the mediastinum and was detected on routine chest radiography. INDEX TERMS:

Lipoma. Mediastinum, neoplasms

REFERENCES

Radiology 118:44, January 1976

1. Alden JF, Bjornson RB, Sterner ER, et al: Mediastinal lipoma. Dis Chest 32:580-581, Nov 1957 2. Brock D, Finger J: Lipoma of heart. Am Heart J 59:591593, Apr 1960 3. Cicciarelli FE, Soule EH, McGoon DC: Lipoma and liposarcoma of the mediastinum: a report of 14 tumors including one lipoma of the thymus. J Thorac Cardiov Surg 47:411-429, Apr 1964 4. Felson B: Chest Roentgenology. Philadelphia, Saunders, 1973 5. Hinshaw HC: Diseases of the Chest. Philadelphia, Saunders, 1969 6. Heuer GJ: Thoracic lipomas. Ann Surg 98:801-819, Nov 1933 7. Keeley JL, Vana AJ: Lipomas of mediastinum-1940 to 1955. Int Abst Surg 103:313-322, 1956 8. Knoernschild HE, Marshall F, Andrews NC: Intrathoracic lipoma: report of successful removal of a large tumor. Ohio Med J 58:1270-1272, Nov 1962 9. Leopold RS: Massive lipoma of mediastinum. Arch Intern Med 26:274-278, 1920 . 10. Saini VK, Wahi PL: Hourglass transmural type of intrathoracic lipoma. J Thorac Cardiov Surg 47:600-604, May 1964 11. Staub EW, Barker WL, Langston HT: Intrathoracic fatty tumors. Dis Chest 47:308-313, Mar 1965 12. Teates CD: Steroid-induced mediastinal lipomatosis. Radiology 96:501-502, Sep 1970 13. Williams WT, Parsons WH: Intrathoracic lipomas. J Thorac Surg 33:785-790, Jun 1957

• A 20-year-old white man was admitted to the hospital for evaluation of a lesion within the chest noted on routine chest radiography. The patient was asymptomatic, and physical examination was normal. Laboratory studies were within normal limits. Chest examination on admission revealed the presence of a 3.5 X 4.0 X 5.0-cm radiolucent mass adjacent to the right heart border and overlying the cardiac silhouette on the lateral examination. Bronchoscopy' was normal, but bronchography of the right lung revealed slight displacement of medial segments of the right middle lobe, and medial basilar segments of the right lower lobe. A lobulated fatty tumor was removed at thoracotomy. Pathologic diagnosis was mediastinal lipoma.

For obscure reasons fatty tissue is detected with difficulty within the mediastinum (4). Lipomas usually present radiographically as water-density shadows inseparable from normal mediastinal contents, and with no distinguishing features to separate them in the differential diagnosis from other mediastinal masses, such as thymoma, lymphoma, and bronchogenic cyst. Perhaps because of the volume of fatty tissue, this patient is the exception to the general rule, with a clearly defined radiolucent mass within the mediastinum. The lesion obscured the heart border, and was separated from the air-containing right lung by a smoothly demarcated soft-tissue stripe. Tomography confirmed these findings.

1 From the Department of Radiology, Burlington County Memorial Hospital, 175 Madison Ave., Mt. Holly, N. J. 08060. Accepted for publication in July 1975. dk

, Fig. 1.

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A and B. Frontal and lateral radiographs of the chest reveal a radiolucent mass within the mediastinum adjacent to the right heart border. Radiographs were obtained with 74-76 kilovoltage technique.

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