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J Thorac Cardiovasc Surg 1999;118:561-563
© 1999 Mosby, Inc.

BRIEF COMMUNICATIONS

THYMOMA ENCASING LAST PATENT VEIN GRAFT TO THE HEART

From the Divisions of Thoracic Surgery and Cardiac Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Mass, and ITESM Medical School, Monterrey, Mexico.

Address for reprints: Michael T. Jaklitsch, MD, Division of Thoracic Surgery, Brigham and Women’s Hospital, 75 Francis St, Boston, MA 02115.

A 64-year-old man had progressive weakness 11 years after coronary artery bypass surgery. In 1987, he received 4 vein grafts to the left anterior descending (LAD), the first obtuse marginal, the ramus, and the posterior descending arteries after a myocardial infarction. During the summer of 1998, he began having progressive ptosis, slurred speech, fatigue, and myalgias. Serum anti-acetylcholine-receptor antibodies and an edrophonium test confirmed the clinical diagnosis of myasthenia gravis. Pyridostigmine, 60 mg 3 times a day, produced symptomatic improvement.

A chest computed tomographic scan identified a 3.5-cm homogeneous anterior mediastinal mass anterior to the pulmonary artery consistent with a thymoma(Fig 1). A partially calcified vein graft was contiguous with the tumor.

View larger version (95K): [in this window] [in a new window]   Fig. 1. Computed tomography of the chest shows a calcified vein graft in the middle of an anterior mediastinal mass (top). A more caudal cut shows a patent vein graft passing between the aorta and the thymic tumor (bottom).

We prepared to remove the only patent vessel providing coronary circulation along with the tumor. The left saphenous vein was harvested. The patient was heparinized and cardiopulmonary bypass (CPB) was established via the left femoral artery and vein before the chest incision. A redo sternotomy was performed without complications and a 4.2-cm upper anterior mediastinal mass was exposed. Manipulation of the sternum was minimized until both pleura were opened wide. The thymoma was attached to the pericardium and the pulmonary artery conus where the pericardium had been opened in 1987. We observed 1-cm erosion into the left pleural space anterior to the hilum without evidence of drop metastases.

The patient was weaned from CPB but the heparin was not reversed. The left internal thoracic artery was prepared for in situ grafting. Initial dissection of the tumor off CPB included the cervical horns of the thymus, division of the thymic veins draining into the innominate vein, and establishment of the lateral margin of resection just anterior to the phrenic nerves. This provided a 1-cm margin from the area of pleural erosion. This dissection was performed without manipulation of the LAD vein graft, which appeared to pass directly through the tumor.

CPB was reestablished and the patient cooled to 25°C. The aorta was crossclamped and the heart protected with antegrade and retrograde boluses of cold blood cardioplegic solution. The thymoma was removed en bloc with the patent saphenous vein graft to the LAD and the occluded vein graft to the ramus(Fig 2).

View larger version (86K): [in this window] [in a new window]   Fig. 2. Gross pathologic specimen viewed from the deep margin shows 2 vein grafts encased by thymoma (arrows). The graft to the ramus branch was occluded. Nearly the entire cardiac blood supply flowed through the patent LAD graft.

Pathologic analysis revealed an epithelial-predominant thymoma with invasion of the surrounding fat. The tumor wrapped around, but did not invade, the walls of the saphenous vein grafts. The deep margin over the pulmonary artery was involved by tumor. The patient was given adjuvant radiation therapy to the mediastinum.

Discussion.

Thymoma accompanies myasthenia gravis in approximately 12% of patients. The use of CPB for the resection of invasive thymomas ^1,2 and the performance of concomitant coronary artery bypass grafting and thymectomy ^3,4 have been described. Although invasion of the tumor into adjacent structures and cardiac entrapment of thymoma ⁵ have been described, to the best of our knowledge there have been no reports of a thymoma entrapping a coronary vein graft.

In this case, the preoperative recognition of tumor entrapment of the only viable vessel to the heart tailored the work-up and surgical sequence. We chose a median sternotomy incision, believing it offered the best exposure for complete excision of the tumor, as well as redoing the bypass grafts. CPB was established via groin cannulas to support the heart during the redo sternotomy. Manipulation of the divided sternum was minimized, because thymomas can adhere to mediastinal structures, even without real invasion. Traction on the tumor or the vein graft might have led to an intraoperative myocardial infarction. Alternatively, a thoracotomy or thoracoscopy could have mobilized the mediastinum from the undersurface of the sternum before sternotomy, but we thought that this did not provide sufficient safety should the vein graft occlude.

A favorable outcome was achieved in this case by (1) preoperative coronary arteriography, (2) femoral CPB before the redo sternotomy, and (3) no manipulation of the tumor or graft before cardioplegia.

References

1. Filippone G, Savona I, Tomasello V, Guzzetta P, Zarcone N, Agate V. Radical excision of invasive thymoma with intracaval and intracardial extension: a successful case report. J Cardiovasc Surg (Torino) 1997;38:547-9.[Medline]
   
2. Fujino S, Tezuka N, Watarida S, Katsuyama K, Inove S, Mori A. Reconstruction of the aortic arch in invasive thymoma under retrograde cerebral perfusion. Ann Thorac Surg 1998;66:263-4.[Abstract/Free Full Text]
   
3. Ohshima K, Ishikawa S, Yoshida I, Ohtaki A, Ohtani Y, Takahashi T, et al. A concomitant operation of coronary artery bypass grafting and thymectomy: a case report [in Japanese]. Kyouba Geka 1994;47:1029-33.
   
4. Mendez-Fernandez MA, Kremem AF, Geis RC, Henly WS. Reconstruction of the left innominate vein in a patient with invasive thymoma undergoing coronary artery bypass surgery. J Cardiovasc Surg 1986;27:351-4.[Medline]
   
5. Allums JA, Gordon FT, Moore CH. Cardiac entrapment by thymoma following coronary bypass surgery. Chest 1979;75:210-1.[Free Full Text]
   

This article has been cited by other articles:

				P. A. Thomas, F. Collart, C. Doddoli, V. Gariboldi, and G. Moulin Nourishing vascularization of a thymoma issued from a left internal thoracic artery graft J. Thorac. Cardiovasc. Surg., May 1, 2006; 131(5): 1196 - 1197. [Full Text] [PDF]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Michael T. Jaklitsch John G. Byrne Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Jaklitsch, M. T. Articles by Mery, C. Search for Related Content PubMed PubMed Citation Articles by Jaklitsch, M. T. Articles by Mery, C.